1. links[index].hash
2. location.hash
3. areaName.hash
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.
See RFC 1738 for complete information about the hash.
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.
height is a read-only property.
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"]>
1. hiddenName.propertyName
2. formName.elements[index].propertyName
<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]
index is an integer representing an entry in the history list.
Property of
window object
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. To obtain the number of entries in the history list, use the length property:
2. history.length
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
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
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
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.
hspace is a read-only property.
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"]>
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
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.)
You can use JavaScript to create an animation with an Image object by repeatedly setting the src property, as shown in Example 4 below. JavaScript animation is slower than GIF animation, because with GIF animation the entire animation is in one file; with JavaScript animation, each frame is in a separate file, and each file must be loaded across the network (host contacted and data transferred).
Image objects do not have onClick, onMouseOut, and onMouseOver event handlers. However, if you define an Area object for the image or place the <IMG> tag within a Link object, you can use the Area or Link object's event handlers. See the Link object.
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].
To use the images array:
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.
To obtain the number of images in a document, use the length property:
2. document.images.lengthdocument.images.length.
Elements in the images array are read-only. For example, the statement 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
stringName.indexOf(searchValue, [fromIndex])
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.
If you do not specify a value for fromIndex, JavaScript assumes zero by default. If searchValue is not found, JavaScript returns -1.
If stringName contains an empty string (""), indexOf returns an empty string.
The indexOf method is case sensitive. For example, the following expression returns -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)
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)
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])
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.
If you do not specify a value for fromIndex, JavaScript assumes stringName.length - 1 (the end of the string) by default. If searchValue is not found, JavaScript returns -1.
The lastIndexOf method is case sensitive. For example, the following expression returns -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.
The last modified date is not a required portion of the header, and some servers do not supply it. If the server does not return the last modified information, JavaScript receives a zero, which it displays as January 1, 1970 GMT. The following code checks the date returned by lastModified and prints out a value that corresponds to unknown.
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
arrayName is the name of an Array object. mimeTypeIndex is either an integer representing a MIME type supported by the plug-in or a string containing the type of a MimeType object (from the type property).
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)
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.
Links created with the link method become elements in the links array. See the Link object for information about the links array.
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.
NAME="anchorName" is used only if the link is also an anchor. It specifies a name for the anchor that then becomes an available hypertext target within the current document. See the Anchor object for details.
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).
linkText is the text or HTML source that the user sees as a hypertext link to the URL.
NAME="mapName" specifies the name of the map. You can specify this map name in the USEMAP attribute of the <IMG> tag.
AREA defines an area of an image as an image map.
NAME="areaName" specifies the name of the Area object. This attribute is not reflected in JavaScript (you cannot refer to an Area object by name).
COORDS specifies the coordinates of the image map.
SHAPE specifies the shape of the map. "default" specifies a region as the default. If omitted, "rect" is used.
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.
propertyName is one of the properties listed below.
Property of
document
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].
To use the links array:
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.
To obtain the number of links in a document, use the length property:
2. document.links.lengthdocument.links.length.
Elements in the links array are read-only. For example, the statement 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
| |
|---|
<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).
methodName is one of the methods listed below.
Property of
window object
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:
Omitting a property name from the location object is equivalent to specifyinglocation.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.
The view-source: protocol displays HTML code that was generated with JavaScript write and writeln methods. For information on printing and saving generated HTML, see the write method.
The about: protocol provides information on Navigator and has the following syntax:
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