1. links[index].hash
2. location.hash
3. areaName.hash
areaName is the value of the NAME attribute of an Area object.
You can set the hash property at any time, although it is safer to set the href property to change a location. If the hash that you specify cannot be found in the current location, you will get an error.
Setting the hash property navigates to the named anchor without reloading the document. This differs from the way a document is loaded when other location properties are set (see "How documents are loaded when location is set").
In event handlers, you must specify
window.location.hash instead of simply using location.hash. Due to the scoping of static objects in JavaScript, a call to location without specifying an object name is equivalent to document.location, which is a synonym for document.URL.
Examples
See the examples for the Anchor object and the href property.
See also
host, hostname, href, pathname, port, protocol, search properties
imageName.height
Implemented in
Navigator 3.0
Tainted?
No
Description
The height property reflects the HEIGHT attribute of the <IMG> tag. For images created with the Image() constructor, the value of the height property is the actual, not the displayed, height of the image.
Examples
The following function displays the values of an image's height, width, hspace, and vspace properties.function showImageSize(theImage) {
alert('height=' + theImage.height+
'; width=' + theImage.width +
'; hspace=' + theImage.hspace +
'; vspace=' + theImage.vspace)
}
See also
border, hspace, vspace, width properties
<INPUT
TYPE="hidden"
NAME="hiddenName"
[VALUE="textValue"]>
VALUE="textValue" specifies the initial value of the Hidden object.
1. hiddenName.propertyName
2. formName.elements[index].propertyName
formName is either the value of the NAME attribute of a Form object or an element in the forms array.
index is an integer representing a Hidden object on a form or the name of a Hidden object as specified by the NAME attribute.
propertyName is one of the properties listed below.
A Hidden object cannot be seen or modified by a user, but you can programmatically change the value of the object by changing its value property. You can use Hidden objects for client/server communication.
<HTML>
<HEAD>
<TITLE>Hidden object example</TITLE>
</HEAD>
<BODY>
<B>Click some of these objects, then click the "Display value" button
<BR>to see the value of the last object clicked.</B>
<FORM NAME="form1">
<INPUT TYPE="hidden" NAME="hiddenObject" VALUE="None">
<P>
<INPUT TYPE="button" VALUE="Click me" NAME="button1"
onClick="document.form1.hiddenObject.value=this.value">
<P>
<INPUT TYPE="radio" NAME="musicChoice" VALUE="soul-and-r&b"
onClick="document.form1.hiddenObject.value=this.value"> Soul and R&B
<INPUT TYPE="radio" NAME="musicChoice" VALUE="jazz"
onClick="document.form1.hiddenObject.value=this.value"> Jazz
<INPUT TYPE="radio" NAME="musicChoice" VALUE="classical"
onClick="document.form1.hiddenObject.value=this.value"> Classical
<P>
<SELECT NAME="music_type_single"
onFocus="document.form1.hiddenObject.value=this.options[this.selectedIndex].text">
<OPTION SELECTED> Red <OPTION> Orange <OPTION> Yellow
</SELECT>
<P><INPUT TYPE="button" VALUE="Display hidden value" NAME="button2"
onClick="alert('Last object clicked: ' + document.form1.hiddenObject.value)">
</FORM>
</BODY>
</HTML>
1. history.propertyName
2. history.methodName(parameters)
3. [windowReference.]history[index]
methodName is one of the methods listed below.
windowReference is a valid way of referring to a window, as described in the window object.
index is an integer representing an entry in the history list.
Property of
window object
To change a window's current URL without generating a history entry, you can use the replace method. This replaces the current page with a new one without generating a history entry. See the replace method.
history[0], history[1], and history[2].To use the history array:
1. history[index]index is an integer representing an entry in the history list.
2. history.length
To obtain the number of entries in the history list, use the length property:
history.length.Elements in the history array are read-only. For example, the statement
history[0]="http://home.netscape.com" has no effect.If you access the history array without specifying an array element, Navigator returns a string of HTML which displays a table of URLs, each of which is a hyperlink.
The history array has the following properties:
| Property |
Description
|
length
|
Reflects the number of history entries in the window
| |
|---|
Methods
The History object has the following methods:
|
|
|
Event handlers
None.
Examples
Example 1. The following example goes to the URL the user visited three clicks ago in the current window.history.go(-3)
Example 2. You can use the history object with a specific window or frame. The following example causes window2 to go back one item in its window (or session) history:window2.history.back()
Example 3. The following example causes the second frame in a frameset to go back one item:parent.frames[1].history.back()
Example 4. The following example causes the frame named frame1 in a frameset to go back one item:parent.frame1.history.back()
Example 5. The following example causes the frame named frame2 in window2 to go back one item:window2.frame2.history.back()
Example 6. The following code determines whether the first entry in the history array contains the string "NETSCAPE". If it does, the function myFunction is called.if (history[0].indexOf("NETSCAPE") != -1) {
Example 7. The following example displays the entire history list:
myFunction(history[0])
}document.writeln("<B>history is</B> " + history)
This code displays output similar to the following:history is
Welcome to Netscape http://home.netscape.com/
Sun Microsystems http://www.sun.com/
SlugVideo at the Dream Inn http://sapphire.cse.ucsc.edu/SlugVideo/dream-inn.html
Bad Dog Chronicles http://www.supernet.net/~dugbrown/
See also
location object, replace method
1. links[index].host
2. location.host
3. areaName.host
areaName is the value of the NAME attribute of an Area object.
You can set the host property at any time, although it is safer to set the href property to change a location. If the host that you specify cannot be found in the current location, you will get an error.
In event handlers, you must specify
window.location.host instead of simply using location.host. Due to the scoping of static objects in JavaScript, a call to location without specifying an object name is equivalent to document.location, which is a synonym for document.URL.See Section 3.1 of RFC 1738 for complete information about the hostname and port.
Examples
See the examples for the href property.
See also
hash, hostname, href, pathname, port, protocol, search properties
1. links[index].hostname
2. location.hostname
3. areaName.hostname
areaName is the value of the NAME attribute of an Area object.
You can set the hostname property at any time, although it is safer to set the href property to change a location. If the hostname that you specify cannot be found in the current location, you will get an error.
In event handlers, you must specify
window.location.hostname instead of simply using location.hostname. Due to the scoping of static objects in JavaScript, a call to location without specifying an object name is equivalent to document.location, which is a synonym for document.URL.See Section 3.1 of RFC 1738 for complete information about the hostname.
Examples
See the examples for the href property.
See also
hash, host, href, pathname, port, protocol, search properties
1. links[index].href
2. location.href
3. areaName.href
areaName is the value of the NAME attribute of an Area object.
You can set the href property at any time.
Omitting a property name from the location object is equivalent to specifying
location.href. For example, the following two statements are equivalent and set the URL of the current window to the Netscape home page:
window.location.href="http://home.netscape.com/"In event handlers, you must specify
window.location="http://home.netscape.com/"
window.location.href instead of simply using location.href. Due to the scoping of static objects in JavaScript, a call to location without specifying an object name is equivalent to document.location, which is a synonym for document.URL.See RFC 1738 for complete information about the URL.
Examples
In the following example, the window.open statement creates a window called newWindow and loads the specified URL into it. The document.write statements display all the properties of newWindow.location in a window called msgWindow.newWindow=window.open
The previous example displays output such as the following:
("http://home.netscape.com/comprod/products/navigator/
version_2.0/script/script_info/objects.html#checkbox_object")
msgWindow.document.write("newWindow.location.href = " +
newWindow.location.href + "<P>")
msgWindow.document.write("newWindow.location.protocol = " +
newWindow.location.protocol + "<P>")
msgWindow.document.write("newWindow.location.host = " +
newWindow.location.host + "<P>")
msgWindow.document.write("newWindow.location.hostName = " +
newWindow.location.hostName + "<P>")
msgWindow.document.write("newWindow.location.port = " +
newWindow.location.port + "<P>")
msgWindow.document.write("newWindow.location.pathname = " +
newWindow.location.pathname + "<P>")
msgWindow.document.write("newWindow.location.hash = " +
newWindow.location.hash + "<P>")
msgWindow.document.write("newWindow.location.search = " +
newWindow.location.search + "<P>")
msgWindow.document.close()newWindow.location.href =
http://home.netscape.com/comprod/products/navigator/
version_2.0/script/script_info/objects.html#checkbox_object
newWindow.location.protocol = http:
newWindow.location.host = home.netscape.com
newWindow.location.hostName = home.netscape.com
newWindow.location.port =
newWindow.location.pathname =
/comprod/products/navigator/version_2.0/script/
script_info/objects.html
newWindow.location.hash = #checkbox_object
newWindow.location.search =
See also
hash, host, hostname, pathname, port, protocol, search properties
imageName.hspace
Implemented in
Navigator 3.0
Tainted?
No
Description
The hspace property reflects the HSPACE attribute of the <IMG> tag. For images created with the Image() constructor, the value of the hspace property is 0.
Examples
See the examples for the height property.
See also
border, height, vspace, width properties
<IMG
[NAME="imageName"]
SRC="Location"
[LOWSRC="Location"]
[HEIGHT="Pixels"|"Value"%]
[WIDTH="Pixels"|"Value"%]
[HSPACE="Pixels"]
[VSPACE="Pixels"]
[BORDER="Pixels"]
[ALIGN="left"|"right"|
"top"|"absmiddle"|"absbottom"|
"texttop"|"middle"|"baseline"|"bottom"]
[ISMAP]
[USEMAP="#MapName"]
[onAbort="handlerText"]
[onError="handlerText"]
[onLoad="handlerText"]>
SRC="Location" specifies the URL of the image to be displayed in the document. You can access this value using the src property.
LOWSRC="Location" specifies the URL of a low-resolution version of the image to be displayed in the document. Navigator loads this smaller image and then replaces it with the larger image specified by SRC. You can access this value using the lowsrc property.
HEIGHT="Pixels"|"Value"% specifies the height of the image either in pixels or as a percentage of the window height. If necessary, Navigator scales the image to fit the space specified by this attribute. You can access this value using the height property.
WIDTH="Pixels"|"Value"% specifies the width of the image either in pixels or as a percentage of the window width. If necessary, Navigator scales the image to fit the space specified by this attribute. You can access this value using the width property.
HSPACE="Pixels" specifies a margin in pixels between the left and right edges of the image and the surrounding text. This attribute applies only to images that use "left" or "right" as the value of the ALIGN attribute. You can access this value using the hspace property.
VSPACE="Pixels" specifies a margin in pixels between the top and bottom edges of the image and the surrounding text. This attribute applies only to images that use "left" or "right" as the value of the ALIGN attribute. You can access this value using the vspace property.
BORDER="Pixels" specifies the width, in pixels, of an image border. You can suppress the border by setting its value to 0; however, if you suppress the border of an image that appears within an anchor, users will not see a colored border indicating that the image is a hyperlink. You can access this value using the border property.
ALIGN specifies the alignment of the image in relation to the surrounding text. Images that are aligned as "left" or "right" float into the next available space on the left or right side of the page, and cause text to wrap around them. Other ALIGN values place the image in a line of text and do not cause the text to wrap. If omitted, "bottom" is used.
ISMAP specifies the image as a server-side image map.
USEMAP="#MapName" specifies the image as a client-side image map. This attribute specifies the # symbol followed by the name of the map. For example,
USEMAP="#areamap".
imageName = new Image([width, height])To use an Image object's properties:
1. imageName.propertyNameTo define an event handler for an Image object created with the Image() constructor:
2. document.images[index].propertyName
3. formName.elements[index].propertyName
1. imageName.onabort = handlerFunction
2. imageName.onerror = handlerFunction
3. imageName.onload = handlerFunction
width is the image width, in pixels.
height is the image height, in pixels.
formName is either the value of the NAME attribute of a Form object or an element in the forms array.
index, when used with the images array is an integer representing an Image object or the name of an Image object as specified by the NAME attribute. index, when used with the elements array, is an integer representing an Image object on a form.
propertyName is one of the properties listed below.
handlerFunction is the keyword null, the name of a function, or a variable or property that contains null or a valid function reference.
Implemented in
Navigator 3.0
Description
The position and size of an image in a document are set when the document is displayed in Navigator and cannot be changed using JavaScript (the width and height properties are read-only). You can change which image is displayed by setting the src and lowsrc properties. (See the descriptions of src and lowsrc.)
The Image() constructor
The primary use for an Image object created with the Image() constructor is to load an image from the network (and decode it) before it is actually needed for display. Then when you need to display the image within an existing image cell, you can set the src property of the displayed image to the same value as that used for the prefetched image, as follows.myImage = new Image()
The resulting image will be obtained from cache, rather than loaded over the network, assuming that sufficient time has elapsed to load and decode the entire image. You can use this technique to create smooth animations, or you could display one of several images based on form input.
myImage.src = "seaotter.gif"
...
document.images[0].src = myImage.src
The images array
You can reference the images in a document by using the images array. This array contains an entry for each Image object (<IMG> tag) in a document in source order (images created with the Image() constructor are not included in the images array). For example, if a document contains three images, these images are reflected as document.images[0], document.images[1], and document.images[2].1. document.images[index]
index is an integer representing an image in a document or the name of an Image object as specified by the NAME attribute.
2. document.images.lengthdocument.images.length.document.images[0]="logo.gif" has no effect.
Properties
The Image object has the following properties:
Note
The border, hspace, name, and vspace properties are not meaningful for images
created with the Image() constructor.
The images array has the following properties:
| Property |
Description
|
length
|
Reflects the number of images in a document
| |
|---|
<IMG NAME="aircraft" SRC="f15e.gif" ALIGN="left" VSPACE="10">The following code refers to the image:
document.aircraft.src='f15e.gif'When you refer to an image by its name, you must include the form name if the image is on a form. The following code refers to the image if it is on a form:
document.myForm.aircraft.src='f15e.gif'Example 2: Create an image with the Image() constructor. The following example creates an Image object, myImage, that is 70 pixels wide and 50 pixels high. If the source URL,
seaotter.gif, does not have dimensions of 70x50 pixels, it is scaled to that size.
myImage = new Image(70, 50)If you omit the width and height arguments from the Image() constructor, myImage is created with dimensions equal to that of the image named in the source URL.
myImage.src = "seaotter.gif"
myImage = new Image()Example 3: Display an image based on form input. In the following example, the user selects which image is displayed. The user orders a shirt by filling out a form. The image displayed depends on the shirt color and size that the user chooses. All possible image choices are pre-loaded to speed response time. When the user clicks the button to order the shirt, the allShirts function displays the images of all the shirts.
myImage.src = "seaotter.gif"
<SCRIPT>Example 4: JavaScript animation. The following example uses JavaScript to create an animation with an Image object by repeatedly changing the value the src property. The script begins by preloading the 10 images that make up the animation (
shirts = new Array()
shirts[0] = "R-S"
shirts[1] = "R-M"
shirts[2] = "R-L"
shirts[3] = "W-S"
shirts[4] = "W-M"
shirts[5] = "W-L"
shirts[6] = "B-S"
shirts[7] = "B-M"
shirts[8] = "B-L"
doneThis = 0
shirtImg = new Array()
// Preload shirt images
for(idx=0; idx < 9; idx++) {
shirtImg[idx] = new Image()
shirtImg[idx].src = "shirt-" + shirts[idx] + ".gif"
}
function changeShirt(form)
{
shirtColor = form.color.options[form.color.selectedIndex].text
shirtSize = form.size.options[form.size.selectedIndex].text
newSrc = "shirt-" + shirtColor.charAt(0) + "-" + shirtSize.charAt(0) + ".gif"
document.shirt.src = newSrc
}
function allShirts()
{
document.shirt.src = shirtImg[doneThis].src
doneThis++
if(doneThis != 9)setTimeout("allShirts()", 500)
else doneThis = 0
return
}
</SCRIPT>
<FONT SIZE=+2><B>Netscape Polo Shirts!</FONT></B>
<TABLE CELLSPACING=20 BORDER=0>
<TR>
<TD><IMG name="shirt" SRC="shirt-W-L.gif"></TD>
<TD>
<FORM>
<B>Color</B>
<SELECT SIZE=3 NAME="color" onChange="changeShirt(this.form)">
<OPTION> Red
<OPTION SELECTED> White
<OPTION> Blue
</SELECT>
<P>
<B>Size</B>
<SELECT SIZE=3 NAME="size" onChange="changeShirt(this.form)">
<OPTION> Small
<OPTION> Medium
<OPTION SELECTED> Large
</SELECT>
<P><INPUT type="button" name="buy" value="Buy This Shirt!"
onClick="allShirts()">
</FORM>
</TD>
</TR>
</TABLE>
image1.gif, image2.gif, image3.gif, and so on). When the Image object is placed on the document with the <IMG> tag, image1.gif is displayed and the onLoad event handler starts the animation by calling the animate function. Notice that the animate function does not call itself after changing the src property of the Image object. This is because when the src property changes, the image's onLoad event handler is triggered and the animate function is called.
<SCRIPT>See also the examples for the onAbort, onError, and onLoad event handlers.
delay = 100
imageNum = 1
// Preload animation images
theImages = new Array()
for(i = 1; i < 11; i++) {
theImages[i] = new Image()
theImages[i].src = "image" + i + ".gif"
}
function animate() {
document.animation.src = theImages[imageNum].src
imageNum++
if(imageNum > 10) {
imageNum = 1
}
}
function slower() {
delay+=10
if(delay > 4000) delay = 4000
}
function faster() {
delay-=10
if(delay < 0) delay = 0
}
</SCRIPT>
<BODY BGCOLOR="white">
<IMG NAME="animation" SRC="image1.gif" ALT="[Animation]"
onLoad="setTimeout('animate()', delay)">
<FORM>
<INPUT TYPE="button" Value="Slower" onClick="slower()">
<INPUT TYPE="button" Value="Faster" onClick="faster()">
</FORM>
</BODY>
See also
Link object; onClick, onMouseOut, onMouseOver event handlers
1. selectName.options[indexValue].index
2. optionName.index
indexValue is an integer representing an option in a Select object.
optionName is the name of a Select object option created using the Option() constructor.
stringName.indexOf(searchValue, [fromIndex])
searchValue is a string or a property of an existing object, representing the value to search for.
fromIndex is the location within the calling string to start the search from. It can be any integer from zero to stringName.length - 1 or a property of an existing object.
Implemented in
Navigator 2.0
Description
Characters in a string are indexed from left to right. The index of the first character is zero, and the index of the last character is stringName.length - 1."Blue Whale".indexOf("blue")
Examples
Example 1. The following example uses indexOf and lastIndexOf to locate values in the string "Brave new world."var anyString="Brave new world"
Example 2. The following example defines two string variables. The variables contain the same string except that the second string contains uppercase letters. The first writeln method displays 19. But because the indexOf method is case sensitive, the string "cheddar" is not found in myCapString, so the second writeln method displays -1.
//Displays 8
document.write("<P>The index of the first w from the beginning is " +
anyString.indexOf("w"))
//Displays 10
document.write("<P>The index of the first w from the end is " +
anyString.lastIndexOf("w"))
//Displays 6
document.write("<P>The index of 'new' from the beginning is " +
anyString.indexOf("new"))
//Displays 6
document.write("<P>The index of 'new' from the end is " +
anyString.lastIndexOf("new"))myString="brie, pepper jack, cheddar"
myCapString="Brie, Pepper Jack, Cheddar"
document.writeln('myString.indexOf("cheddar") is ' +
myString.indexOf("cheddar"))
document.writeln('<P>myCapString.indexOf("cheddar") is ' +
myCapString.indexOf("cheddar"))
See also
charAt, lastIndexOf, split methods
isNaN(testValue)
On platforms that support NaN, the parseFloat and parseInt functions return "NaN" when they evaluate a value that is not a number. isNaN returns true if passed "NaN," and false otherwise.
floatValue=parseFloat(toFloat)
if (isNaN(floatValue)) {
notFloat()
} else {
isFloat()
}
stringName.italics()
Implemented in
Navigator 2.0
Description
Use the italics method with the write or writeln methods to format and display a string in a document.
Examples
The following example uses string methods to change the formatting of a string:var worldString="Hello, world"
The previous example produces the same output as the following HTML:
document.write(worldString.blink())
document.write("<P>" + worldString.bold())
document.write("<P>" + worldString.italics())
document.write("<P>" + worldString.strike())<BLINK>Hello, world</BLINK>
<P><B>Hello, world</B>
<P><I>Hello, world</I>
<P><STRIKE>Hello, world</STRIKE>
See also
blink, bold, strike methods
navigator.javaEnabled()
Implemented in
Navigator 3.0
Description
javaEnabled returns true if Java is enabled, false otherwise. The user can enable or disable Java by choosing Network Preferences from the Navigator's Options menu.
Examples
The following code executes function1 if Java is enabled; otherwise it executes function2.if (navigator.javaEnabled()) {
function1()
}
else function2()
See also
appCodeName, appName, userAgent properties
arrayName.join(separator)
separator specifies a string to separate each element of the array. The separator is converted to a string if necessary. If omitted, the array elements are separated with a comma (,).
Implemented in
Navigator 3.0
Description
The string conversion of all array elements are joined into one string.
Examples
The following example creates an array, a with three elements, then joins the array three times: using the default separator, then a comma and a space, and then a plus.a = new Array("Wind","Rain","Fire")
This code produces the following output:
document.write(a.join() +"<BR>")
document.write(a.join(", ") +"<BR>")
document.write(a.join(" + ") +"<BR>")Wind,Rain,Fire
Wind, Rain, Fire
Wind + Rain + Fire
See also
reverse, sort methods
stringName.lastIndexOf(searchValue, [fromIndex])
searchValue is a string or a property of an existing object, representing the value to search for.
fromIndex is the location within the calling string to start the search from. It can be any integer from zero to stringName.length - 1 or a property of an existing object.
Implemented in
Navigator 2.0
Description
Characters in a string are indexed from left to right. The index of the first character is zero, and the index of the last character is stringName.length - 1."Blue Whale, Killer Whale".lastIndexOf("blue")
Examples
The following example uses indexOf and lastIndexOf to locate values in the string "Brave new world."var anyString="Brave new world"
//Displays 8
document.write("<P>The index of the first w from the beginning is " +
anyString.indexOf("w"))
//Displays 10
document.write("<P>The index of the first w from the end is " +
anyString.lastIndexOf("w"))
//Displays 6
document.write("<P>The index of 'new' from the beginning is " +
anyString.indexOf("new"))
//Displays 6
document.write("<P>The index of 'new' from the end is " +
anyString.lastIndexOf("new"))
See also
charAt, indexOf, split methods
document.lastModified
Implemented in
Navigator 2.0
Tainted?
Yes
Description
The lastModified property is derived from the HTTP header data sent by the web server. Servers generally obtain this date by examining the file's modification date.lastmod = document.lastModified // get string of last modified date
lastModified is a read-only property.
lastmoddate = Date.parse(lastmod) // convert modified string to date
if(lastmoddate == 0){ // unknown date (or January 1,
// 1970 GMT)
document.writeln("Lastmodified: Unknown")
} else {
document.writeln("LastModified: " + lastmod)
}
Examples
In the following example, the lastModified property is used in a <SCRIPT> tag at the end of an HTML file to display the modification date of the page:document.write("This page updated on " + document.lastModified)
1. formName.lengthWhen used with array properties:
2. frameReference.length
3. history.length
4. radioName.length
5. selectName.length
6. stringName.length
7. windowReference.length
8. arrayName.length
9. anchors.length
10. applets.length
11. arguments.length
12. elements.length
13. embeds.length
14. forms.length
15. frames.length
16. history.length
17. images.length
18. links.length
19. mimeTypes.length
20. plugins.length
21. plugins[mimeTypeIndex].length
22. selectName.options.length
frameReference is either the value of the NAME attribute of a frame or an element in the frames array.
radioName is either the value of the NAME attribute of a Radio object or an element in the elements array.
selectName is either the value of the NAME attribute of a Select object or an element in the elements array.
stringName is any string or a property of an existing object.
windowReference is a valid way of referring to a window, as described in the window object.
arrayName is the name of an Array object.
For a null string, length is zero. For a Select object, the values returned by form 5 and form 22 of the syntax are the same. For a window containing frames, the values returned by form 7 and form 15 of the syntax are the same. For a Form object, the values returned by form 1 and form 12 of the syntax are the same. For a frame containing frames, the values returned by form 2 and form 15 of the syntax are the same.
For arrays, you can set the length property to truncate an array at any time. You cannot extend an array; for example, if you set length to 3 when it is currently 2, the array will still contain only 2 elements. For information on other ways to change the length of an array, see the Array object.
function getChoice() {
for (var i = 0; i < document.musicForm.musicType.length; i++) {
if (document.musicForm.musicType.options[i].selected == true) {
return document.musicForm.musicType.options[i].text
}
}
}
The following example displays 8 in an Alert dialog box:
var x="Netscape"The following example shortens the array statesUS to a length of 50 if the current length is greater than 50.
alert("The string length is " + x.length)
if (statesUS.length > 50) {
statesUS.length=50
alert("The U.S. has only 50 states. New length is " + statesUS.length)
}
linkText.link(hrefAttribute)
hrefAttribute is any string that specifies the HREF attribute of the <A> tag; it should be a valid URL (relative or absolute).
Implemented in
Navigator 2.0
Description
Use the link method to programmatically create a hypertext link, and then call write or writeln to display the link in a document.
Examples
The following example displays the word "Netscape" as a hypertext link that returns the user to the Netscape home page:
var hotText="Netscape"
The previous example produces the same output as the following HTML:
var URL="http://home.netscape.com"
document.write("Click to return to " + hotText.link(URL))Click to return to <A HREF="http://home.netscape.com">Netscape</A>
See also
Anchor object
<A HREF=locationOrURLYou can also define a link using the link method.
[NAME="anchorName"]
[TARGET="windowName"]
[onClick="handlerText"]
[onMouseOut="handlerText"]>
[onMouseOver="handlerText"]>
linkText
</A>
To define an area, use standard HTML syntax with the addition of JavaScript event handlers:
<MAP NAME="mapName">
<AREA
[NAME="areaName"]
COORDS="x1,y1,x2,y2,..."|"x-center,y-center,radius"
HREF="locationOrURL"
[SHAPE="rect"|"poly"|"circle"|"default"]
[TARGET="windowName"]
[onMouseOut="handlerText"]
[onMouseOver="handlerText"]>
</MAP>
HTML attributes
HREF=locationOrURL identifies a destination anchor or URL. For areas, any region of an image that does not have an HREF attribute does not function as a hyperlink. For areas, this attribute is required if you include the onMouseOut and onMouseOver event handlers. See the location object for a description of the URL components.
TARGET="windowName" specifies the frame or window that the link is loaded into. windowName can be an existing window; it can be a frame name specified in a <FRAMESET> tag; or it can be one of the literal frame names _top, _parent, _self, or _blank. It cannot be a JavaScript expression (for example, it cannot be parent.frameName or windowName.frameName).
Syntax
To use a Link or Area object's properties:
document.links[index].propertyName
Parameters
index is an integer representing a Link or Area object or the name of a Link or Area object as specified by the NAME attribute.
Property of
document
If a Link object is also an Anchor object, the object has entries in both the anchors and links arrays.
When a user clicks a Link object and navigates to the destination document (specified by HREF=locationOrURL), the destination document's referrer property contains the URL of the source document. Evaluate the referrer property from the destination document.
You can use a Link object to execute a JavaScript function rather than link to a hypertext reference by specifying the
javascript: URL protocol for the link's HREF attribute. You might want to do this if the link surrounds an Image object and you want to execute JavaScript code when the image is clicked. Or you might want to use a link instead of a button to execute JavaScript code.
For example, when a user clicks the following links, the slower and faster functions execute:
<A HREF="javascript:slower()">Slower</A>You can use a Link object to do nothing rather than link to a hypertext reference by specifying the
<A HREF="javascript:faster()">Faster</A>
javascript:void(0) URL protocol for the link's HREF attribute. You might want to do this if the link surrounds an Image object and you want to use the link's event handlers with the image. When a user clicks the following link or image, nothing happens:
<A HREF="javascript:void(0)">Click here to do nothing</A>
<A HREF="javascript:void(0)">
<IMG SRC="images\globe.gif" ALIGN="top" HEIGHT="50" WIDTH="50">
</A>
document.links[0], document.links[1], and document.links[2]. For information on the links array, see "The links array".
The HREF attribute is required for Area objects that use the onMouseOut or onMouseOver event handlers. However, if you create an Area for an image and do not want the image to link to a hypertext reference when clicked, specify a JavaScript function in the area's HREF attribute by using the
javascript: URL protocol. For example, if a user clicks the following Area object, the function onTop executes.
<MAP NAME="worldMap">
If you want an area's link to do nothing, use
<AREA NAME="topWorld" COORDS="0,0,50,25" HREF="javascript:onTop()"
onMouseOver="self.status='You are on top of the world';return true"
onMouseOut="self.status='You have left the top of the world';return true">
</MAP>javascript:void(0) in the HREF attribute. When the user clicks the following Area object, nothing happens:
<MAP NAME="worldMap">
<AREA NAME="topWorld" COORDS="0,0,50,25" HREF="javascript:void(0)"
onMouseOver="self.status='You are on top of the world';return true"
onMouseOut="self.status='You have left the top of the world';return true">
</MAP>
The links array
You can reference the Area and Link objects in your code by using the links array. This array contains an entry for each Area (<AREA HREF="..."> tag) and Link (<A HREF=""> tag) object in a document in source order. It also contains links created with the link method.For example, if a document contains three Link objects, these links are reflected as document.links[0], document.links[1], and document.links[2].
1. document.links[index]
index is an integer representing a link in a document or the name of a Link object as specified by the NAME attribute.
2. document.links.lengthdocument.links.length.
document.links[0]="link1" has no effect.
Properties
The Area and Link objects have the following properties:
The links array has the following property:
| Property |
Description
|
length
|
Reflects the number of links in a document
| |
|---|
Link objects have the following event handlers:
<A HREF="#javascript_intro">Introduction to JavaScript</A>Example 2. The following example creates a hypertext link to an anchor named numbers in the file
doc3.html in the window window2. If window2 does not exist, it is created.
<LI><A HREF=doc3.html#numbers TARGET="window2">Numbers</A>Example 3. The following example takes the user back x entries in the history list:
<A HREF="javascript:history.go(-1 * x)">Click here</A>Example 4. The following example creates a hypertext link to a URL. The user can use the set of radio buttons to choose between three URLs. The link's onClick event handler sets the URL (the link's href property) based on the selected radio button. The link also has an onMouseOver event handler that changes the window's status property. As the example shows, you must return true to set the
window.status property in the onMouseOver event handler.
<SCRIPT>Example 5: links array. In the following example, the linkGetter function uses the links array to display the value of each link in the current document. The example also defines several links and a button for running linkGetter.
var destHREF="http://home.netscape.com/"
</SCRIPT>
<FORM NAME="form1">
<B>Choose a destination from the following list, then click "Click me" below.</B>
<BR><INPUT TYPE="radio" NAME="destination" VALUE="netscape"
onClick="destHREF='http://home.netscape.com/'"> Netscape home page
<BR><INPUT TYPE="radio" NAME="destination" VALUE="sun"
onClick="destHREF='http://www.sun.com/'"> Sun home page
<BR><INPUT TYPE="radio" NAME="destination" VALUE="rfc1867"
onClick="destHREF='http://www.ics.uci.edu/pub/ietf/html/rfc1867.txt'"> RFC 1867
<P><A HREF=""
onMouseOver="window.status='Click this if you dare!'; return true"
onClick="this.href=destHREF">
<B>Click me</B></A>
</FORM>
function linkGetter() {
msgWindow=window.open("","msg","width=400,height=400")
msgWindow.document.write("links.length is " +
document.links.length + "<BR>")
for (var i = 0; i < document.links.length; i++) {
msgWindow.document.write(document.links[i] + "<BR>")
}
}
<A HREF="http://home.netscape.com">Netscape Home Page</A>
<A HREF="http://www.catalog.com/fwcfc/">China Adoptions</A>
<A HREF="http://www.supernet.net/~dugbrown/">Bad Dog Chronicles</A>
<A HREF="http://www.best.com/~doghouse/homecnt.shtml">Lab Rescue</A>
<P>
<INPUT TYPE="button" VALUE="Display links"
onClick="linkGetter()">
Example 6: Area object with onMouseOver and onMouseOut event handlers. The following example displays an image, globe.gif. The image uses an image map that defines areas for the top half and the bottom half of the image. The onMouseOver and onMouseOut event handlers display different status bar messages depending on whether the mouse passes over or leaves the top half or bottom half of the image. The HREF attribute is required when using the onMouseOver and onMouseOut event handlers, but in this example the image does not need a hypertext link, so the HREF attribute executes javascript:void(0), which does nothing (see "void" for more information).
<MAP NAME="worldMap">
Example 7: Refer to Area object with links array. The following code refers to the href property of the first Area
<AREA NAME="topWorld" COORDS="0,0,50,25" HREF="javascript:void(0)"
onMouseOver="self.status='You are on top of the world';return true"
onMouseOut="self.status='You have left the top of the world';return true">
<AREA NAME="bottomWorld" COORDS="0,25,50,50" HREF="javascript:void(0)"
onMouseOver="self.status='You are on the bottom of the world';return true"
onMouseOut="self.status='You have left the bottom of the world';return true">
</MAP>
<IMG SRC="images\globe.gif" ALIGN="top" HEIGHT="50" WIDTH="50" USEMAP="#worldMap"> object shown in Example 1.
document.links[0].href
Example 8: Simulate an Area object's onClick using the HREF attribute. The following example uses an Area object's HREF attribute to execute a JavaScript function. The image displayed, colors.gif, shows two sample colors. The top half of the image is the color "antiquewhite", and the bottom half is "white". When the user clicks the top or bottom half of the image, the function setBGColor changes the document's background color to the color shown in the image.
<SCRIPT>
function setBGColor(theColor) {
document.bgColor=theColor
}
</SCRIPT>
Click the color you want for this document's background color
<MAP NAME="colorMap">
<AREA NAME="topColor" COORDS="0,0,50,25" HREF="javascript:setBGColor('antiquewhite')">
<AREA NAME="bottomColor" COORDS="0,25,50,50" HREF="javascript:setBGColor('white')">
</MAP>
<IMG SRC="images\colors.gif" ALIGN="top" HEIGHT="50" WIDTH="50" USEMAP="#colorMap">
See also
Anchor object, Image object; link method
document.linkColor
Implemented in
Navigator 2.0
Tainted?
No
Description
The linkColor property is expressed as a hexadecimal RGB triplet or as one of the string literals listed in "Color values". This property is the JavaScript reflection of the LINK attribute of the <BODY> tag. The default value of this property is set by the user on the Colors tab of the Preferences dialog box, which is displayed by choosing General Preferences from the Options menu. You cannot set this property after the HTML source has been through layout.
If you express the color as a hexadecimal RGB triplet, you must use the format rrggbb. For example, the hexadecimal RGB values for salmon are red=FA, green=80, and blue=72, so the RGB triplet for salmon is "FA8072."
Examples
The following example sets the color of document links to aqua using a string literal:
document.linkColor="aqua"
The following example sets the color of document links to aqua using a hexadecimal triplet:
document.linkColor="00FFFF"
See also
alinkColor, bgColor, fgColor, vlinkColor properties
Math.LN2
Implemented in
Navigator 2.0
Tainted?
No
Description
Because LN2 is a constant, it is a read-only property of Math.
Examples
The following function returns the natural log of two:
function getNatLog2() {
return Math.LN2
}
See also
E, LN10, LOG2E, LOG10E, PI, SQRT1_2, SQRT2 properties
Math.LN10
Implemented in
Navigator 2.0
Tainted?
No
Description
Because LN10 is a constant, it is a read-only property of Math.
Examples
The following function returns the natural log of 10:
function getNatLog10() {
return Math.LN10
}
See also
E, LN2, LOG2E, LOG10E, PI, SQRT1_2, SQRT2 properties
[windowReference.]location[.propertyName]
[windowReference.]location.methodName(parameters)
propertyName is one of the properties listed below. Omitting the property name is equivalent to specifying the href property (the complete URL).
Property of
window object
The following diagram of a URL shows the relationships between the location properties:
protocol//host:port/pathname#hash?searchFor example:
http://home.netscape.com/assist/extensions.html#topic1?x=7&y=2Following is a description of each part of the URL diagram:
The location object has two other properties not shown in the diagram above:
location.href. For example, the following two statements are equivalent and set the URL of the current window to the Netscape home page:
window.location.href="http://home.netscape.com/"The location object is contained by the window object and is within its scope. If you reference a location object without specifying a window, the location object represents the current location. If you reference a location object and specify a window name, for example, windowReference
window.location="http://home.netscape.com/"
.location
.propertyName, the location object represents the location of the specified window.
In event handlers, you must specify
window.location instead of simply using location. Due to the scoping of static objects in JavaScript, a call to location without specifying an object name is equivalent to document.location, which is a synonym for document.URL.
Do not use location as a property of the document object; use the document.URL property instead. The document.location property, which is a synonym for document.URL, will be removed in a future release.
The javascript: protocol evaluates the expression after the colon (:), if there is one, and loads a page containing the string value of the expression, unless it is undefined. If the expression evaluates to undefined (by calling a void function, for example
javascript:void(0)), no new page loads. Note that loading a new page over your script's page clears the page's variables, functions, and so on.
about:[cache|plugins]
Methods
The location object has the following methods:
|
|
|
Event handlers
None.
Examples
Example 1. The following two statements are equivalent and set the URL of the current window to the Netscape home page:
window.location.href="http://home.netscape.com/"
Example 2. The following statement sets the URL of a frame named frame2 to the Sun home page:
window.location="http://home.netscape.com/"parent.frame2.location.href="http://www.sun.com/"
See also the examples for the Anchor object.
See also
history object; URL property
Math.log(number)
Implemented in
Navigator 2.0
Description
If the value of number is outside the suggested range, the return value is always -1.797693134862316e+308.
Examples
The following function returns the natural log of the variable x:
function getLog(x) {
If you pass getLog the value 10, it returns 2.302585092994046; if you pass it the value zero, it returns -1.797693134862316e+308 because zero is out of range.
return Math.log(x)
}
See also
exp, pow methods
Math.LOG2E
Implemented in
Navigator 2.0
Tainted?
No
Description
Because LOG2E is a constant, it is a read-only property of Math.
Examples
The following function returns the base 2 logarithm of E:
function getLog2e() {
return Math.LOG2E
}
See also
E, LN2, LN10, LOG10E, PI, SQRT1_2, SQRT2 properties
Math.LOG10E
Implemented in
Navigator 2.0
Tainted?
No
Description
Because LOG10E is a constant, it is a read-only property of Math.
Examples
The following function returns the base 10 logarithm of E:
function getLog10e() {
return Math.LOG10E
}
See also
E, LN2, LN10, LOG2E, PI, SQRT1_2, SQRT2 properties
imageName.lowsrc
Implemented in
Navigator 3.0
Tainted?
No
Description
The lowsrc property initially reflects the LOWSRC attribute of the <IMG> tag. Navigator loads the smaller image specified by lowsrc and then replaces it with the larger image specified by the src property. You can change the lowsrc property at any time.
Examples
See the examples for the src property.
See also
complete, src properties