his chapter is an alphabetical reference of all objects, properties, methods, event handlers, and functions.
his chapter is an alphabetical reference of all objects, properties, methods, event handlers, and functions.
Math.abs(number)
Implemented in
Navigator 2.0
Examples
The following function returns the absolute value of the variable x:
function getAbs(x) {
return Math.abs(x)
}
Math.acos(number)
Implemented in
Navigator 2.0
Description
The acos method returns a numeric value between zero and pi radians. If the value of number is outside this range, it returns zero.
Examples
The following function returns the arc cosine of the variable x:
function getAcos(x) {
If you pass getAcos the value -1, it returns 3.141592653589793; if you pass it the value two, it returns zero because two is out of range.
return Math.acos(x)
} See also
asin, atan, atan2, cos, sin, tan methods
formName.action
Implemented in
Navigator 2.0
Description
The action property is a reflection of the ACTION attribute of the <FORM> tag. Each section of a URL contains different information. See the location object for a description of the URL components.
You can set the action property at any time.
Examples
The following example sets the action property of the musicForm form to the value of the variable urlName:
document.musicForm.action=urlName
See also
encoding, method, target properties; Form object
alert("message")
Implemented in
Navigator 2.0
Description
Use the alert method to display a message that does not require a user decision. The message argument specifies a message that the dialog box contains.
Although alert is a method of the window object, you do not need to specify a windowReference when you call it. For example, windowReference.alert() is unnecessary.
Examples
In the following example, the testValue function checks the name entered by a user in the Text object of a form to make sure that it is no more than eight characters in length. This example uses the alert method to prompt the user to enter a valid value.
function testValue(textElement) {
You can call the testValue function in the onBlur event handler of a form's Text object, as shown in the following example:
if (textElement.length > 8) {
alert("Please enter a name that is 8 characters or less")
}
}Name: <INPUT TYPE="text" NAME="userName"
onBlur="testValue(userName.value)"> See also
confirm, prompt methods
document.alinkColor
Implemented in
Navigator 2.0
Description
The alinkColor 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 ALINK attribute of the <BODY> tag. 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 active links using a string literal:
document.alinkColor="aqua"
The following example sets the color of active links to aqua using a hexadecimal triplet:
document.alinkColor="00FFFF"
See also
bgColor, fgColor, linkColor, vlinkColor properties
text.anchor(nameAttribute)
Implemented in
Navigator 2.0
Description
Use the anchor method with the write or writeln methods to programmatically create and display an anchor in a document. Create the anchor with the anchor method, and then call write or writeln to display the anchor in a document. In LiveWire, use the write function to display the anchor.
In the syntax, the text string represents the literal text that you want the user to see. The nameAttribute string represents the NAME attribute of the <A> tag.
Anchors created with the anchor method become elements in the anchors array. See the Anchor object for information about the anchors array.
Examples
The following example opens the msgWindow window and creates an anchor for the Table of Contents:
var myString="Table of Contents"
The previous example produces the same output as the following HTML:
msgWindow.document.writeln(myString.anchor("contents_anchor"))<A NAME="contents_anchor">Table of Contents</A>
In LiveWire, you can generate this HTML by calling the write function instead of using document.writeln.
See also
link method
<A [HREF=locationOrURL]You can also define an anchor using the anchor method.
NAME="anchorName"
[TARGET="windowName"]>
anchorText
</A>
HTML attributes
HREF=locationOrURL is used only if the anchor is also a link. It identifies a destination anchor or URL for the link. See the Link object for details.
NAME="anchorName" specifies a name for the anchor. A link to the anchor uses this value for its HREF attribute.
TARGET="windowName" is used only if the anchor is also a link. It specifies the window that the link is loaded into. See the Link object for details.
anchorText specifies the text or HTML source to display at the anchor.
Property of
document
Implemented in
Navigator 2.0
Description
If an Anchor object is also a Link object, the object has entries in both the anchors and links arrays.
The anchors array
You can reference the Anchor objects in your code by using the anchors array. This array contains an entry for each <A> tag containing a NAME attribute in a document in source order. For example, if a document contains three named anchors, these anchors are reflected as document.anchors[0], document.anchors[1], and document.anchors[2].
To use the anchors array:
1. document.anchors[index]
index is an integer representing an anchor in a document.
To obtain the number of anchors in a document, use the length property:
2. document.anchors.lengthdocument.anchors.length. If a document names anchors in a systematic way using natural numbers, you can use the anchors array and its length property to validate an anchor name before using it in operations such as setting location.hash. See the example below.
Elements in the anchors array are read-only. For example, the statement document.anchors[0]="anchor1" has no effect.
Properties
The anchors object has no properties.
The anchors array has the following properties:
| Property |
Description
|
length |
Reflects the number of named anchors in the document |
|
|---|
Methods
None
Event handlers
None
Examples
Example 1: An anchor. The following example defines an anchor for the text "Welcome to JavaScript":
<A NAME="javascript_intro"><H2>Welcome to JavaScript</H2></A>
If the preceding anchor is in a file called intro.html, a link in another file could define a jump to the anchor as follows:
<A HREF="intro.html#javascript_intro">Introduction</A>
Example 2: anchors array. The following example opens two windows. The first window contains a series of buttons that set location.hash in the second window to a specific anchor. The second window defines four anchors named "0," "1," "2," and "3." (The anchor names in the document are therefore 0, 1, 2, ... (document.anchors.length-1).) When a button is pressed in the first window, the onClick event handler verifies that the anchor exists before setting window2.location.hash to the specified anchor name.
link1.html, which defines the first window and its buttons, contains the following code:
<HTML>
<HEAD>
<TITLE>Links and Anchors: Window 1</TITLE>
</HEAD>
<BODY>
<SCRIPT>
window2=open("link2.html","secondLinkWindow",
"scrollbars=yes,width=250, height=400")
function linkToWindow(num) {
if (window2.document.anchors.length > num)
window2.location.hash=num
else
alert("Anchor does not exist!")
}
</SCRIPT>
<B>Links and Anchors</B>
<FORM>
<P>Click a button to display that anchor in window #2
<P><INPUT TYPE="button" VALUE="0" NAME="link0_button"
onClick="linkToWindow(this.value)">
<INPUT TYPE="button" VALUE="1" NAME="link0_button"
onClick="linkToWindow(this.value)">
<INPUT TYPE="button" VALUE="2" NAME="link0_button"
onClick="linkToWindow(this.value)">
<INPUT TYPE="button" VALUE="3" NAME="link0_button"
onClick="linkToWindow(this.value)">
<INPUT TYPE="button" VALUE="4" NAME="link0_button"
onClick="linkToWindow(this.value)">
</FORM>
</BODY>
</HTML>link2.html, which contains the anchors, contains the following code:
<HTML>
<HEAD>
<TITLE>Links and Anchors: Window 2</TITLE>
</HEAD>
<BODY>
<A NAME="0"><B>Some numbers</B> (Anchor 0)</A>
<UL><LI>one
<LI>two
<LI>three
<LI>four</UL>
<P><A NAME="1"><B>Some colors</B> (Anchor 1)</A>
<UL><LI>red
<LI>orange
<LI>yellow
<LI>green</UL>
<P><A NAME="2"><B>Some music types</B> (Anchor 2)</A>
<UL><LI>R&B
<LI>Jazz
<LI>Soul
<LI>Reggae
<LI>Rock</UL>
<P><A NAME="3"><B>Some countries</B> (Anchor 3)</A>
<UL><LI>Afghanistan
<LI>Brazil
<LI>Canada
<LI>Finland
<LI>India</UL>
</BODY>
</HTML> See also
Link object, anchor method
navigator.appCodeName
Implemented in
Navigator 2.0
Description
appCodeName is a read-only property.
Examples
The following example displays the value of the appCodeName property:
document.write("The value of navigator.appCodeName is " +
For Navigator 2.0, this displays the following:
navigator.appCodeName)The value of navigator.appCodeName is Mozilla
See also
appName, appVersion, javaEnabled, userAgent properties
<APPLET
CODE=classFileName
HEIGHT=height
WIDTH=width
MAYSCRIPT
[NAME=appletName]
[CODEBASE=classFileDirectory]
[ALT=alternateText]
[ALIGN="left"|"right"|
"top"|"absmiddle"|"absbottom"|
"texttop"|"middle"|"baseline"|"bottom"]
[HSPACE=spaceInPixels]
[VSPACE=spaceInPixels]>
[<PARAM NAME=parameterName VALUE=parameterValue>]
[ ... <PARAM>]
</APPLET>
.class extension.
HEIGHT=height specifies the height of the applet in pixels within the browser window.
WIDTH=width specifies the width of the applet in pixels within the browser window.
MAYSCRIPT permits the applet to access JavaScript. Use this attribute to prevent an applet from accessing JavaScript on a page without your knowledge.
NAME=appletName specifies the name of the applet.
CODEBASE=classFileDirectory specifies directory of the .class file, if it is different from the directory that contains the HTML page.
ALT=alternateText specifies text to display for browsers that do not support the <APPLET> tag.
ALIGN=alignment specifies the alignment of the applet on the HTML page.
HSPACE=spaceInPixels specifies a horizontal margin for the applet, in pixels, within the browser window.
VSPACE=spaceInPixels specifies a vertical margin for the applet, in pixels, within the browser window.
<PARAM> defines a parameter for the applet.
NAME=parameterName specifies the name of the parameter.
VALUE=parameterValue> specifies a value for the parameter.
Implemented in
Navigator 3.0
Description
The author of an HTML page must permit an applet to access JavaScript by specifying the MAYSCRIPT attribute of the <APPLET> tag. This prevents an applet from accessing JavaScript on a page without the knowledge of the page author. For example, to allow the musicPicker.class applet access to JavaScript on your page, specify the following:
<APPLET CODE = "musicPicker.class" WIDTH=200 HEIGHT=35
Accessing JavaScript when the MAYSCRIPT attribute is not specified results in an exception.
For more information on using applets, see Chapter 4, "LiveConnect communication."
NAME="musicApp" MAYSCRIPT>
The applets array
You can reference the applets in your code by using the applets array. This array contains an entry for each Applet object (<APPLET> tag) in a document in source order. For example, if a document contains three applets, these applets are reflected as document.applets[0], document.applets[1], and document.applets[2].
To use the applets array:
1. document.applets[index]
index is an integer representing an applet in a document or a string containing the name of an Applet object.
To obtain the number of applets in a document, use the length property:
2. document.applets.lengthdocument.applets.length.
Elements in the applets array are read-only. For example, the statement document.applets[0]="myApplet.class" has no effect.
Properties
None.
Methods
Event handlers
Examples
The following code launches an applet called "musicApp":
<APPLET CODE="musicSelect.class" WIDTH=200 HEIGHT=35
For more examples, see Chapter 4, "LiveConnect communication."
NAME="musicApp" MAYSCRIPT>
</APPLET>
See also
MimeType, Plugin objects
navigator.appName
Implemented in
Navigator 2.0
Description
appName is a read-only property.
Examples
The following example displays the value of the appName property:
document.write("The value of navigator.appName is " +
For Navigator 2.0, this displays the following:
navigator.appName)The value of navigator.appName is Netscape
See also
appCodeName, appVersion, javaEnabled, userAgent properties
navigator.appVersion
Implemented in
Navigator 2.0
Description
The appVersion property specifies version information in the following format:
releaseNumber (platform; country)
The values contained in this format are the following:
document.write("The value of navigator.appVersion is " +
navigator.appVersion)
For Navigator 2.0 on Windows 95, this displays the following:
The value of navigator.appVersion is 2.0 (Win95, I)Example 2. The following example populates a Textarea object with newline characters separating each line. Because the newline character varies from platform to platform, the example tests the appVersion property to determine whether the user is running Windows (appVersion contains "Win" for all versions of Windows). If the user is running Windows, the newline character is set to rn; otherwise, it's set to n, which is the newline character for Unix and Macintosh.
<SCRIPT>
var newline=null
function populate(textareaObject){
if (navigator.appVersion.lastIndexOf('Win') != -1)
newline="rn"
else newline="n"
textareaObject.value="line 1" + newline + "line 2" + newline
+ "line 3"
}
</SCRIPT>
<FORM NAME="form1">
<BR><TEXTAREA NAME="testLines" ROWS=8 COLS=55></TEXTAREA>
<P><INPUT TYPE="button" VALUE="Populate the Textarea object"
onClick="populate(document.form1.testLines)">
</TEXTAREA>
</FORM>
<MAP NAME="mapName">
<AREA
[NAME="areaName"]
COORDS="x1,y1,x2,y2,..."|"x-center,y-center,radius"
HREF="location"
[SHAPE="rect"|"poly"|"circle"|"default"]
[TARGET="windowName"]
[onMouseOut="handlerText"]
[onMouseOver="handlerText"]>
</MAP>
1. areaName.propertyName
2. document.links[index].propertyName
Implemented in
Navigator 3.0
Description
Area objects are in the links array. You cannot refer to an Area object by name; you must use the links array. For example, if a document contains three Area objects, these objects are reflected as document.links[0], document.links[1], and document.links[2]. For information on the links array, see the Link object.
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> Properties
The Area object has the following properties:
Methods
None
Event handlers
Examples
Example 1: 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 the void operator for more information).
<MAP NAME="worldMap">
Example 2: Refer to 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="imagesglobe.gif" ALIGN="top" HEIGHT="50" WIDTH="50" USEMAP="#worldMap"> object shown in Example 1.
document.links[0].href
Example 3: Simulate onClick with 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="imagescolors.gif" ALIGN="top" HEIGHT="50" WIDTH="50" USEMAP="#colorMap"> See also
Image object
1. functionName.arguments[index]To use the arguments array from within a function or Function object:
2. functionName.arguments.length
this.arguments[index]
this.arguments[index].length
| Property |
Description
|
length |
Reflects the number of arguments to the function |
|
|---|
Examples
This example defines a function that creates HTML lists. The only formal argument for the function is a string that is "U" if the list is to be unordered (bulleted), or "O" if the list is to be ordered (numbered). The function is defined as follows:
function list(type) {
You can pass any number of arguments to this function, and it displays each argument as an item in the type of list indicated. For example, the following call to the function
document.write("<" + type + "L>")
for (var i=1; i<list.arguments.length; i++) {
document.write("<LI>" + list.arguments[i])
document.write("</" + type + "L>") }
}list("U", "One", "Two", "Three")
results in this output:
<UL>
In LiveWire, you can display the same output by calling the write function instead of using
<LI>One
<LI>Two
<LI>Three
</UL>document.write.
1. arrayObjectName = new Array()To use Array objects:
2. arrayObjectName = new Array(arrayLength)
1. arrayObjectName.propertyName
2. arrayObjectName.methodName(parameters)
billingMethod = new Array(5)When you create an array, all of its elements are initially null. The following code creates an array of 25 elements, then assigns values to the first three elements:
musicTypes = new Array(25)An array's length increases if you assign a value to an element higher than the current length of the array. The following code creates an array of length zero, then assigns a value to element 99. This changes the length of the array to 100.
musicTypes[0] = "R&B"
musicTypes[1] = "Blues"
musicTypes[2] = "Jazz"
colors = new Array()You can construct a dense array of two or more elements starting with index 0 if you define initial values for all elements. A dense array is one in which each element has a value. The following code creates a dense array with three elements:
colors[99] = "midnightblue"
myArray = new Array("Hello", myVar, 3.14159)
| Property |
Description
|
length |
Reflects the number of elements in an array |
prototype |
Lets you add a properties to an Array object. |
|
|---|
Methods
Event handlers
Examples
The following example creates an array, msgArray, with a length of 0, then assigns values to msgArray[0] and msgArray[99], changing the length of the array to 100.
msgArray = new Array()
See also the examples for the onError event handler.
msgArray [0] = "Hello"
msgArray [99] = "world"
if (msgArray .length == 100) // This is true, because defined msgArray [99] element.
document.write("The length is 100.")
Math.asin(number)
Implemented in
Navigator 2.0
Description
The asin method returns a numeric value between -pi/2 and pi/2 radians. If the value of number is outside this range, it returns zero.
Examples
The following function returns the arc sine of the variable x:
function getAsin(x) {
If you pass getAsin the value one, it returns 1.570796326794897 (pi/2); if you pass it the value two, it returns zero because two is out of range.
return Math.asin(x)
} See also
acos, atan, atan2, cos, sin, tan methods
Math.atan(number)
Implemented in
Navigator 2.0
Description
The atan method returns a numeric value between -pi/2 and pi/2 radians.
Examples
The following function returns the arc tangent of the variable x:
function getAtan(x) {
If you pass getAtan the value 1, it returns 0.7853981633974483; if you pass it the value .5, it returns 0.4636476090008061.
return Math.atan(x)
} See also
acos, asin, atan2, cos, sin, tan methods
Math.atan2(x,y)
Implemented in
Navigator 2.0
Description
The atan2 method returns a numeric value.
Examples
The following function returns the angle of the polar coordinate:
function getAtan2(x,y) {
If you pass getAtan2 the values (90,15), it returns 1.4056476493802699; if you pass it the values (15,90), it returns 0.16514867741462683.
return Math.atan2(x,y)
} See also
acos, asin, atan, cos, sin, tan methods
history.back()
Implemented in
Navigator 2.0
Description
This method performs the same action as a user choosing the Back button in the Navigator. The back method is the same as history.go(-1).
Examples
The following custom buttons perform the same operations as the Navigator Back and Forward buttons:
<P><INPUT TYPE="button" VALUE="< Back"
onClick="history.back()">
<P><INPUT TYPE="button" VALUE="> Forward"
onClick="history.forward()"> See also
forward, go methods
document.bgColor
Implemented in
Navigator 2.0
Description
The bgColor 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 BGCOLOR 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 can set the bgColor property at any time.
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 the document background to aqua using a string literal:
document.bgColor="aqua"
The following example sets the color of the document background to aqua using a hexadecimal triplet:
document.bgColor="00FFFF"
See also
alinkColor, fgColor, linkColor, vlinkColor properties
stringName.big()
Implemented in
Navigator 2.0
Description
Use the big method with the write or writeln methods to format and display a string in a document. In LiveWire, use the write function to display the string.
Examples
The following example uses string methods to change the size of a string:
var worldString="Hello, world"
The previous example produces the same output as the following HTML:
document.write(worldString.small())
document.write("<P>" + worldString.big())
document.write("<P>" + worldString.fontsize(7))<SMALL>Hello, world</SMALL>
In LiveWire, you can generate this HTML by calling the write function instead of using
<P><BIG>Hello, world</BIG>
<P><FONTSIZE=7>Hello, world</FONTSIZE>document.write.
See also
fontsize, small methods
stringName.blink()
Implemented in
Navigator 2.0
Description
Use the blink method with the write or writeln methods to format and display a string in a document. In LiveWire, use the write function to display the string.
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>
In LiveWire, you can generate this HTML by calling the write function instead of using
<P><B>Hello, world</B>
<P><I>Hello, world</I>
<P><STRIKE>Hello, world</STRIKE>document.write.
See also
bold, italics, strike methods
1. passwordName.blur()
2. selectName.blur()
3. textName.blur()
4. textareaName.blur()
5. frameReference.blur()
6. windowReference.blur()
windowReference is a valid way of referring to a window, as described in the window object.
Method of
Frame object, Password object, Select object, Text object, Textarea object, window object
Implemented in
Description
Use the blur method to remove focus from a specific form element.
The blur method removes focus from the window or frame. Removing focus from a window sends the window to the background in most windowing systems.
Examples
The following example removes focus from the password element userPass:
userPass.blur()
This example assumes that the password is defined as
<INPUT TYPE="password" NAME="userPass">
See also
focus method, select method
stringName.bold()
Implemented in
Navigator 2.0
Description
Use the bold method with the write or writeln methods to format and display a string in a document. In LiveWire, use the write function to display the string.
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>
In LiveWire, you can generate this HTML by calling the write function instead of using
<P><B>Hello, world</B>
<P><I>Hello, world</I>
<P><STRIKE>Hello, world</STRIKE>document.write.
See also
blink, italics, strike methods
imageName.border
Implemented in
Navigator 3.0
Description
The border property reflects the BORDER attribute of the <IMG> tag. For images created with the Image() constructor, the value of the border property is 0.
border is a read-only property.
Examples
The following function displays the value of an image's border property if the value is not zero.
function checkBorder(theImage) {
if (theImage.border==0) {
alert('The image has no border!')
}
else alert('The image's border is ' + theImage.border)
} See also
height, hspace, vspace, width properties
<INPUT
TYPE="button"
NAME="buttonName"
VALUE="buttonText"
[onClick="handlerText"]>
1. buttonName.propertyName
2. buttonName.methodName(parameters)
3. formName.elements[index].propertyName
4. formName.elements[index].methodName(parameters)
Implemented in
Description
A Button object on a form looks as follows:
A Button object is a form element and must be defined within a <FORM> tag.
The Button object is a custom button that you can use to perform an action you define. The button executes the script specified by its onClick event handler.
Properties
The Button object has the following properties:
| Property |
Description
|
name |
Reflects the NAME attribute |
type |
Reflects the TYPE attribute |
value |
Reflects the VALUE attribute |
|
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Examples
The following example creates a button named calcButton. The text "Calculate" is displayed on the face of the button. When the button is clicked, the function calcFunction is called.
<INPUT TYPE="button" VALUE="Calculate" NAME="calcButton"
onClick="calcFunction(this.form)"> See also
Form object, Reset object, Submit object
Math.ceil(number)
Implemented in
Navigator 2.0
Examples
The following function returns the ceil value of the variable x:
function getCeil(x) {
If you pass getCeil the value 45.95, it returns 46; if you pass it the value -45.95, it returns -45.
return Math.ceil(x)
} See also
floor method
stringName.charAt(index)
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 the index you supply is out of range, JavaScript returns an empty string.
Examples
The following example displays characters at different locations in the string "Brave new world":
var anyString="Brave new world"
In LiveWire, you can display the same output by calling the write function instead of using
document.write("The character at index 0 is " + anyString.charAt(0))
document.write("The character at index 1 is " + anyString.charAt(1))
document.write("The character at index 2 is " + anyString.charAt(2))
document.write("The character at index 3 is " + anyString.charAt(3))
document.write("The character at index 4 is " + anyString.charAt(4))document.write.
See also
indexOf, lastIndexOf, split methods
<INPUT
TYPE="checkbox"
NAME="checkboxName"
VALUE="checkboxValue"
[CHECKED]
[onClick="handlerText"]>
textToDisplay
1. checkboxName.propertyName
2. checkboxName.methodName(parameters)
3. formName.elements[index].propertyName
4. formName.elements[index].methodName(parameters)
Examples
Example 1. The following example displays a group of four checkboxes that all appear checked by default:
<B>Specify your music preferences (check all that apply):</B>
Example 2. The following example contains a form with three text boxes and one checkbox. The user can use the checkbox to choose whether the text fields are converted to uppercase. Each text field has an onChange event handler that converts the field value to uppercase if the checkbox is checked. The checkbox has an onClick event handler that converts all fields to uppercase when the user checks the checkbox.
<BR><INPUT TYPE="checkbox" NAME="musicpref_rnb" CHECKED> R&B
<BR><INPUT TYPE="checkbox" NAME="musicpref_jazz" CHECKED> Jazz
<BR><INPUT TYPE="checkbox" NAME="musicpref_blues" CHECKED> Blues
<BR><INPUT TYPE="checkbox" NAME="musicpref_newage" CHECKED> New Age<HTML>
<HEAD>
<TITLE>Checkbox object example</TITLE>
</HEAD>
<SCRIPT>
function convertField(field) {
if (document.form1.convertUpper.checked) {
field.value = field.value.toUpperCase()}
}
function convertAllFields() {
document.form1.lastName.value = document.form1.lastName.value.toUpperCase()
document.form1.firstName.value = document.form1.firstName.value.toUpperCase()
document.form1.cityName.value = document.form1.cityName.value.toUpperCase()
}
</SCRIPT>
<BODY>
<FORM NAME="form1">
<B>Last name:</B>
<INPUT TYPE="text" NAME="lastName" SIZE=20 onChange="convertField(this)">
<BR><B>First name:</B>
<INPUT TYPE="text" NAME="firstName" SIZE=20 onChange="convertField(this)">
<BR><B>City:</B>
<INPUT TYPE="text" NAME="cityName" SIZE=20 onChange="convertField(this)">
<P><INPUT TYPE="checkBox" NAME="convertUpper"
onClick="if (this.checked) {convertAllFields()}"
> Convert fields to upper case
</FORM>
</BODY>
</HTML> See also
Form, Radio objects
1. checkboxName.checked
2. radioName[index].checked
Implemented in
Navigator 2.0
Description
If a checkbox or radio button is selected, the value of its checked property is true; otherwise, it is false.
You can set the checked property at any time. The display of the checkbox or radio button updates immediately when you set the checked property.
Examples
The following example examines an array of radio buttons called musicType on the musicForm form to determine which button is selected. The VALUE attribute of the selected button is assigned to the checkedButton variable.
function stateChecker() {
var checkedButton = ""
for (var i in document.musicForm.musicType) {
if (document.musicForm.musicType[i].checked=="1") {
checkedButton=document.musicForm.musicType[i].value
}
}
} See also
defaultChecked property
clearTimeout(timeoutID)
Implemented in
Navigator 2.0
Description
See the description for the setTimeout method.
Examples
See the examples for the setTimeout method.
See also
setTimeout method
1. buttonName.click()
2. radioName[index].click()
3. checkboxName.click()
Implemented in
Navigator 2.0
Description
The effect of the click method varies according to the calling element:
Examples
The following example toggles the selection status of the first radio button in the musicType Radio object on the musicForm form:
document.musicForm.musicType[0].click()
The following example toggles the selection status of the newAge checkbox on the musicForm form:
document.musicForm.newAge.click()
document.close()
Implemented in
Navigator 2.0
Description
The close method closes a stream opened with the document.open() method. If the stream was opened to layout, the close method forces the content of the stream to display. Font style tags, such as <BIG> and <CENTER>, automatically flush a layout stream.
The close method also stops the "meteor shower" in the Netscape icon and displays "Document: Done" in the status bar.
Examples
The following function calls document.close() to close a stream that was opened with document.open(). The document.close() method forces the content of the stream to display in the window.
function windowWriter1() {
var myString = "Hello, world!"
msgWindow.document.open()
msgWindow.document.write(myString + "<P>")
msgWindow.document.close()
} See also
open (document object), write, writeln methods
windowReference.close()
Implemented in
Description
The close method closes the specified window. If you call close without specifying a windowReference, JavaScript closes the current window.
The close method closes only windows opened by JavaScript using the open method. If you attempt to close any other window, a confirm is generated, which lets the user choose whether the window closes. This is a security feature to prevent "mail bombs" containing self.close(). However, if the window has only one document (the current one) in its session history, the close is allowed without any confirm. This is a special case for one-off windows that need to open other windows and then dispose of themselves.
In event handlers, you must specify window.close() instead of simply using close(). Due to the scoping of static objects in JavaScript, a call to close() without specifying an object name is equivalent to document.close().
Examples
Any of the following examples closes the current window:
window.close()
The following example closes the messageWin window:
self.close()
close()messageWin.close()
This example assumes that the window was opened in a manner similar to the following:
messageWin=window.open("")
See also
open (window object) method
imageName.complete
Implemented in
Navigator 3.0
Description
complete is a read-only property.
Examples
The following example displays an image and three radio buttons. The user can click the radio buttons to choose which image is displayed. Clicking another button lets the user see the current value of the complete property.
<B>Choose an image:</B>
<BR><INPUT TYPE="radio" NAME="imageChoice" VALUE="image1" CHECKED
onClick="document.images[0].src='f15e.gif'">F-15 Eagle
<BR><INPUT TYPE="radio" NAME="imageChoice" VALUE="image2"
onClick="document.images[0].src='f15e2.gif'">F-15 Eagle 2
<BR><INPUT TYPE="radio" NAME="imageChoice" VALUE="image3"
onClick="document.images[0].src='ah64.gif'">AH-64 Apache
<BR><INPUT TYPE="button" VALUE="Is the image completely loaded?"
onClick="alert('The value of the complete property is '
+ document.images[0].complete)">
<BR>
<IMG NAME="aircraft" SRC="f15e.gif" ALIGN="left" VSPACE="10"><BR> See also
lowsrc, src properties
confirm("message")
Implemented in
Navigator 2.0
Description
Use the confirm method to ask the user to make a decision that requires either an OK or a Cancel. The message argument specifies a message that prompts the user for the decision. The confirm method returns true if the user chooses OK and false if the user chooses Cancel.
Although confirm is a method of the window object, you do not need to specify a windowReference when you call it. For example, windowReference.confirm() is unnecessary.
Examples
This example uses the confirm method in the confirmCleanUp function to confirm that the user of an application really wants to quit. If the user chooses OK, the custom cleanUp function closes the application.
function confirmCleanUp() {
You can call the confirmCleanUp function in the onClick event handler of a form's pushbutton, as shown in the following example:
if (confirm("Are you sure you want to quit this application?")) {
cleanUp()
}
}<INPUT TYPE="button" VALUE="Quit" onClick="confirmCleanUp()">
See also
alert, prompt methods
cookies.txt file.
document.cookie
Implemented in
Navigator 2.0
Description
Use string methods such as substring, charAt, indexOf, and lastIndexOf to determine the value stored in the cookie. See the Appendix C, "Netscape cookies" for a complete specification of the cookie syntax.
You can set the cookie property at any time.
The "expires=" component in the cookie file sets an expiration date for the cookie, so it persists beyond the current browser session. This date string is formatted as follows:
Wdy, DD-Mon-YY HH:MM:SS GMT
This format represents the following values:
expires=Wednesday, 09-Nov-99 23:12:40 GMTThe cookie date format is the same as the date returned by toGMTString, with the following exceptions:
function RecordReminder(time, expression) {
// Record a cookie of the form "@<T>=<E>" to map
// from <T> in milliseconds since the epoch,
// returned by Date.getTime(), onto an encoded expression,
// <E> (encoded to contain no white space, semicolon,
// or comma characters)
document.cookie = "@" + time + "=" + expression + ";"
// set the cookie expiration time to one day
// beyond the reminder time
document.cookie += "expires=" + cookieDate(time + 24*60*60*1000)
// cookieDate is a function that formats the date
//according to the cookie spec
}
Math.cos(number)
Implemented in
Navigator 2.0
Description
The cos method returns a numeric value between -1 and one, which represents the cosine of the angle.
Examples
The following function returns the cosine of the variable x:
function getCos(x) {
If x equals
return Math.cos(x)
}Math.PI/2, getCos returns 6.123031769111886e-017; if x equals Math.PI, getCos returns -1.
See also
acos, asin, atan, atan2, sin, tan methods