Math.tan(number)
Description
The tan method returns a numeric value that represents the tangent of the angle.
Examples
The following function returns the tangent of the variable x:
function getTan(x) {
return Math.tan(x)
}
If you pass getTan the value Math.PI/4, it returns 0.9999999999999999.
See also
acos, asin, atan, cos, sin methods
target
Property. For form, a string specifying the name of the window that responses go to after a form has been submitted. For link, a string specifying the name of the window that displays the content of a clicked hypertext link.
Syntax
1. formName.target
2. links[index].target
Parameters
formName is either the name of a form or an element in the forms array.
index is an integer representing a link object.
Property of
form object, link object
Description
The target property initially reflects the TARGET attribute of the FORM and A tags; however, setting target overrides these attributes.
You can set target using a string, if the string represents a window name. You can set the target property at any time.
Examples
The following example specifies that responses to the musicInfo form are displayed in the msgWindow window:
document.musicInfo.target="msgWindow"
See also
For form: action, encoding, method properties; form object
text object
Object. A text input field on an HTML form. The user can enter a word, phrase, or series of numbers in a text field.
HTML syntax
To define a text object, use standard HTML syntax with the addition of the onBlur, onChange, onFocus, and onSelect event handlers:
<INPUT
TYPE="text"
NAME="textName"
VALUE="textValue"
SIZE=integer
[onBlur="handlerText"]
[onChange="handlerText"]
[onFocus="handlerText"]
[onSelect="handlerText"]>
HTML attributes
NAME="textName" specifies the name of the text object. You can access this value using the name property.
VALUE="textValue" specifies the initial value of the text object. You can access this value using the defaultValue property.
SIZE=integer specifies the number of characters the text object can accommodate without scrolling.
Syntax
To use a text object's properties and methods:
1. textName.propertyName
2. textName.methodName(parameters)
3. formName.elements[index].propertyName
4. formName.elements[index].methodName(parameters)
Parameters
textName is the value of the NAME attribute of a text object.
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 text object on a form.
propertyName is one of the properties listed below.
methodName is one of the methods listed below.
Property of
form
Description
A text object on a form looks as follows:
A text object is a form element and must be defined within a FORM tag.
text objects can be updated (redrawn) dynamically by setting the value property (this.value).
Properties
The text object has the following properties:
Property | Description |
---|---|
defaultValue | Reflects the VALUE attribute |
name | Reflects the NAME attribute |
value | Reflects the current value of the text object's field |
<B>Last name:</B> <INPUT TYPE="text" NAME="last_name" VALUE="" SIZE=25>Example 2. The following example creates two text objects on a form. Each object has a default value. The city object has an onFocus event handler that selects all the text in the field when the user tabs to that field. The state object has an onChange event handler that forces the value to uppercase.
<FORM NAME="form1"> <BR><B>City: </B><INPUT TYPE="text" NAME="city" VALUE="Anchorage" SIZE="20" onFocus="this.select()"> <B>State: </B><INPUT TYPE="text" NAME="state" VALUE="AK" SIZE="2" onChange="this.value=this.value.toUpperCase()"> </FORM>See also the examples for the onBlur, onChange, onFocus, and onSelect event handlers.
See also
form, password, string, textarea objects
text property
Property. A string specifying the text that follows an OPTION tag in a select object.
Syntax
selectName.options[index].text
Parameters
selectName is either the value of the NAME attribute of a select object or an element in the elements array.
index is an integer representing an option in a select object.
Property of
options array (see select object)
Description
The text property initially reflects the text that follows an OPTION tag in a select object.
You can set the text property at any time; however, the following effects result:
Examples
In the following example, the getChoice function returns the value of the text property for the selected option. The for loop evaluates every option in the musicType select object. The if statement finds the option that is selected.
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
}
}
return null
}
The previous example assumes that the select object is similar to the following:
<SELECT NAME="musicType">
<OPTION SELECTED> R&B
<OPTION> Jazz
<OPTION> Blues
<OPTION> New Age
</SELECT>
textarea
Object. A multiline input field on an HTML form. The user can use a textarea field to enter words, phrases, or numbers.
HTML syntax
To define a text area, use standard HTML syntax with the addition of the onBlur, onChange, onFocus, and onSelect event handlers:
<TEXTAREA
NAME="textareaName"
ROWS="integer"
COLS="integer"
[onBlur="handlerText"]
[onChange="handlerText"]
[onFocus="handlerText"]
[onSelect="handlerText"]>
textToDisplay
</TEXTAREA>
HTML attributes
NAME="textareaName" specifies the name of the textarea object. You can access this value using the name property.
ROWS="integer" and COLS="integer" define the physical size of the displayed input field in numbers of characters.
textToDisplay specifies the initial value of the textarea object. A textarea allows only ASCII text, and new lines are respected. You can access this value using the defaultValue property.
Syntax
To use a textarea object's properties and methods:
1. textareaName.propertyName
2. textareaName.methodName(parameters)
3. formName.elements[index].propertyName
4. formName.elements[index].methodName(parameters)
Parameters
textareaName is the value of the NAME attribute of a textarea object.
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 textarea object on a form.
propertyName is one of the properties listed below.
methodName is one of the methods listed below.
Property of
form
Description
A textarea object on a form looks as follows:
A textarea object is a form element and must be defined within a FORM tag.
textarea objects can be updated (redrawn) dynamically by setting the value property (this.value).
To begin a new line in a textarea object, you can use a newline character. This character varies from platform to platform: Unix is n, Windows is rn, and Macintosh is n. One way to enter a newline character programmatically is to test the appVersion property to determine the current platform and set the newline character accordingly. See the appVersion property for an example.
Properties
The textarea object has the following properties:
Property | Description |
---|---|
defaultValue | Reflects the VALUE attribute |
name | Reflects the NAME attribute |
value | Reflects the current value of the textarea object |
Methods
Event handlers
Examples
The following example creates a textarea object that is six rows long and fifty-five columns wide. The textarea field appears immediately below the word "Description:". When the form loads, the textarea object contains several lines of data, including one blank line.
<B>Description:</B>
<BR><TEXTAREA NAME="item_description" ROWS=6 COLS=55>
Our storage ottoman provides an attractive way to
store lots of CDs and videos--and it's versatile
enough to store other things as well.
It can hold up to 72 CDs under the lid and 20 videos
in the drawer below.
</TEXTAREA>
See also the examples for the onBlur, onChange, onFocus, and onSelect event handlers.
See also
form object, password object, string object, text object
title
Property. A string representing the title of a document.
Syntax
document.title
Property of
document
Description
The title property is a reflection of the value specified within the <TITLE> and </TITLE> tags. If a document does not have a title, the title property is null.
title is a read-only property.
Examples
In the following example, the value of the title property is assigned to a variable called docTitle:
var newWindow = window.open("http://www.netscape.com")
var docTitle = newWindow.document.title
toGMTString
Method. Converts a date to a string, using the Internet GMT conventions.
Syntax
dateObjectName.toGMTString()
Parameters
dateObjectName is either the name of a Date object or a property of an existing object.
Method of
Date
Description
The exact format of the value returned by toGMTString varies according to the platform.
Examples
In the following example, today is a Date object:
today.toGMTString()
In this example, the toGMTString method converts the date to GMT (UTC) using the operating system's time-zone offset and returns a string value that is similar to the following form. The exact format depends on the platform.
Mon, 18 Dec 1995 17:28:35 GMT
See also
toLocaleString method
toLocaleString
Method. Converts a date to a string, using the current locale's conventions.
Syntax
dateObjectName.toLocaleString()
Parameters
dateObjectName is either the name of a Date object or a property of an existing object.
Method of
Date
Description
If you are trying to pass a date using toLocaleString, be aware that different locales assemble the string in different ways. Using methods such as getHours, getMinutes, and getSeconds gives more portable results.
Examples
In the following example, today is a Date object:
today.toLocaleString()
In this example, toLocaleString returns a string value that is similar to the following form. The exact format depends on the platform.
12/18/95 17:28:35
See also
toGMTString method
toLowerCase
Method. Returns the calling string value converted to lowercase.
Syntax
stringName.toLowerCase()
Parameters
stringName is any string or a property of an existing object.
Method of
string
Description
The toLowerCase method returns the value of stringName converted to lowercase. toLowerCase does not affect the value of stringName itself.
Examples
The following example displays the lowercase string "alphabet":
var upperText="ALPHABET"
document.write(upperText.toLowerCase())
In LiveWire, you can generate the same output by calling the write function instead of using document.write
.
See also
toUpperCase method
top
Property. The top property is a synonym for the top-most Navigator window, which is a "document window" or "Web Browser window."
Syntax
1. top.propertyName
2. top.methodName
3. top.frameName
4. top.frames[index]
Parameters
propertyName is defaultStatus, status, or length.
methodName is any method associated with the window object.
frameName and frames[index] are ways to refer to frames.
Property of
window object
Description
The top property refers to the top-most window that contains frames or nested framesets. Use the top property to refer to this ancestor window.
The top property is read-only. The value of the top property is
<object objectReference>
where objectReference is an internal reference.
Examples
The statement top.close()
closes the top-most ancestor window.
The statement top.length
specifies the number of frames contained within the top-most ancestor window. When the top-most ancestor is defined as follows, top.length
returns three:
<FRAMESET COLS="30%,40%,30%">
<FRAME SRC=child1.htm NAME="childFrame1">
<FRAME SRC=child2.htm NAME="childFrame2">
<FRAME SRC=child3.htm NAME="childFrame3">
</FRAMESET>
The following example sets the background color of a frame called myFrame to red. myFrame is a child of the top-most ancestor window.
top.myFrame.document.bgColor="red"
toUpperCase
Method. Returns the calling string value converted to uppercase.
Syntax
stringName.toUpperCase()
Parameters
stringName is any string or a property of an existing object.
Method of
string
Description
The toUpperCase method returns the value of stringName converted to uppercase. toUpperCase does not affect the value of stringName itself.
Examples
The following example displays the string "ALPHABET":
var lowerText="alphabet"
document.write(lowerText.toUpperCase())
In LiveWire, you can generate the same output by calling the write function instead of using document.write
.
See also
toLowerCase method
unescape
Function. Returns the ASCII string for the specified value.
Syntax
unescape("string")
Parameters
string is a string or a property of an existing object, containing characters in either of the following forms:
Description
The string returned by the unescape function is a series of characters in the ISO Latin-1 character set. The unescape function is a top-level JavaScript function not associated with any object.
Examples
The following example returns "&":
unescape("%26")
The following example returns "!#":
unescape("%21%23")
See also
escape function
URL property
Property. A string specifying the complete URL of the document.
Syntax
document.URL
Property of
document
Description
URL is a read-only property of document containing the full URL of the document. URL is a string-valued property that usually matches what window.location.href is set to when you load the document, but redirection may change location.href.
Examples
The following example displays the URL of the current document:
document.write("The current URL is " + document.URL)
See also
href
userAgent
Property. A string representing the value of the user-agent header sent in the HTTP protocol from client to server.
Syntax
navigator.userAgent
Property of
navigator
Description
Servers use the value sent in the user-agent header to identify the client.
userAgent is a read-only property.
Examples
The following example displays userAgent information for the Navigator:
document.write("The value of navigator.userAgent is " +
navigator.userAgent)
For Navigator 2.0, this displays the following:
The value of navigator.userAgent is Mozilla/2.0 (Win16; I)
See also
appCodeName, appName, appVersion properties
UTC
Method. Returns the number of milliseconds in a Date object since January 1, 1970, 00:00:00, Universal Coordinated Time (GMT).
Syntax
Date.UTC(year, month, day [, hrs] [, min] [, sec])
Parameters
year is a year after 1900.
month is a month between zero and eleven.
date is a day of the month between one and thirty-one.
hrs is hours between zero and twenty-three.
min is minutes between zero and fifty-nine.
sec is seconds between zero and fifty-nine.
Method of
Date
Description
UTC takes comma-delimited date parameters and returns the number of milliseconds since January 1, 1970, 00:00:00, Universal Coordinated Time (GMT).
Because UTC is a static method of Date, you always use it as Date.UTC()
, rather than as a method of a Date object you created.
Examples
The following statement creates a Date object using GMT instead of local time:
gmtDate = new Date(Date.UTC(96, 11, 1, 0, 0, 0))
See also
parse method
value
Property. A string that is related to the VALUE attribute of its object.
Syntax
1. objectName.value
2. radioName[index].value
3. selectName.options.[index].value
Parameters
objectName is either the value of the NAME attribute of a hidden, password, text, textarea, button, reset, submit, or checkbox object or an element in the elements array.
radioName is the value of the NAME attribute of a radio object.
selectName is either the value of the NAME attribute of a select object or an element in the elements array.
index is an integer representing a radio button in a radio object or an option in a select object.
Property of
Description
The value property differs for every object.
hidden, text, and textarea objects
The value property is a string that initially reflects the VALUE attribute. This string is displayed in the text and textarea fields. The value of this property changes when a user or a program modifies the field.
You can set the value property at any time. The display of the text and textarea objects updates immediately when you set the value property.
password object
The value property is a string that initially reflects the VALUE attribute. This string is represented by asterisks in the password object field. The value of this property changes when a user or a program modifies the field, but the value is always displayed as asterisks.
If you programmatically set the value property and then evaluate it, JavaScript returns the current value. If a user interactively modifies the value in the password field, you cannot evaluate it accurately for security reasons.
button, reset, and submit objects
When a VALUE attribute is specified in HTML, the value property is a string that reflects it. This string is displayed on the face of the button.
When a VALUE attribute is not specified in HTML, the value property differs for each object:
options array
The value property is a string that initially reflects the VALUE attribute. The value of this property can change when a program modifies it. The value property is not displayed on-screen but is returned to the server if the option is selected.
You can set the value property at any time.
Do not confuse the value property with the selection state of the select object or the text that is displayed as an option. The selected and selectedIndex properties determine which options are selected, and the defaultSelected property determines the default selection state. The text that is displayed in each option is specified by its text property.
checkbox and radio objects
When a VALUE attribute is specified in HTML, the value property is a string that reflects it. When a VALUE attribute is not specified in HTML, the value property is a string that evaluates to "on." The value property is not displayed on-screen but is returned to the server if the radio button or checkbox is selected.
You can set the value property at any time.
Do not confuse the value property with the selection state of the object or the text that is displayed next to each checkbox and radio button. The checked property determines the selection state of the object, and the defaultChecked property determines the default selection state. The text that is displayed is specified following the INPUT TYPE="checkbox" or the INPUT TYPE="radio" tag.
Examples
The following function evaluates the value property of a group of buttons and displays it in the msgWindow window:
function valueGetter() {
var msgWindow=window.open("")
msgWindow.document.write("submitButton.value is " +
document.valueTest.submitButton.value + "<BR>")
msgWindow.document.write("resetButton.value is " +
document.valueTest.resetButton.value + "<BR>")
msgWindow.document.write("helpButton.value is " +
document.valueTest.helpButton.value + "<BR>")
msgWindow.document.close()
}
This example displays the following values:
Query Submit
Reset
Help
The previous example assumes the buttons have been defined as follows:
<INPUT TYPE="submit" NAME="submitButton">
<INPUT TYPE="reset" NAME="resetButton">
<INPUT TYPE="button" NAME="helpButton" VALUE="Help">
The following function evaluates the value property of a group of radio buttons and displays it in the msgWindow window:
function valueGetter() {
var msgWindow=window.open("")
for (var i = 0; i < document.valueTest.radioObj.length; i++) {
msgWindow.document.write
("The value of radioObj[" + i + "] is " +
document.valueTest.radioObj[i].value +"<BR>")
}
msgWindow.document.close()
}
This example displays the following values:
on
on
on
on
The previous example assumes the buttons have been defined as follows:
<BR><INPUT TYPE="radio" NAME="radioObj">R&B
<BR><INPUT TYPE="radio" NAME="radioObj" CHECKED>Soul
<BR><INPUT TYPE="radio" NAME="radioObj">Rock and Roll
<BR><INPUT TYPE="radio" NAME="radioObj">Blues
See also
vlinkColor
Property. A string specifying the color of visited links.
Syntax
document.vlinkColor
Property of
document
Description
The vlinkColor 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 VLINK 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 visited links to aqua using a string literal:
document.vlinkColor="aqua"
The following example sets the color of active links to aqua using a hexadecimal triplet:
document.vlinkColor="00FFFF"
See also
alinkColor, bgColor, fgColor, linkColor properties
window object
Object. The top-level object for each document, location, and history object group.
Syntax
To define a window, use the open method:
windowVar = window.open("URL", "windowName" [,"windowFeatures"])
For details on defining a window, see the open (window object) method.
To use a window object's properties and methods:
1. window.propertyName
2. window.methodName(parameters)
3. self.propertyName
4. self.methodName(parameters)
5. top.propertyName
6. top.methodName(parameters)
7. parent.propertyName
8. parent.methodName(parameters)
9. windowVar.propertyName
10. windowVar.methodName(parameters)
11. propertyName
12. methodName(parameters)
To define an onLoad or onUnload event handler for a window object, use the BODY or FRAMESET tags:
<BODY
...
[onLoad="handlerText"]
[onUnload="handlerText"]>
</BODY>
<FRAMESET
ROWS="rowHeightList"
COLS="columnWidthList"
[onLoad="handlerText"]
[onUnload="handlerText"]>
[<FRAME SRC="locationOrURL" NAME="frameName">]
</FRAMESET>
For information on the BODY and FRAMESET tags, see the document and frame objects.
Parameters
windowVar is the name of a new window. Use this variable when referring to a window's properties, methods, and containership.
windowName is the window name to use in the TARGET attribute of a FORM or A tag.
propertyName is one of the properties listed below.
methodName is one of the methods listed below.
Property of
None
Description
The window object is the top-level object in the JavaScript client hierarchy. frame objects are also windows.
The self and window properties are synonyms for the current window, and you can optionally use them to refer to the current window. For example, you can close the current window by calling either window.close()
or self.close()
. You can use these properties to make your code more readable or to disambiguate the property reference self.status
from a form called status
. See the properties and methods listed below for more examples.
The top and parent properties are also synonyms that can be used in place of the window name. top refers to the top-most Navigator window, and parent refers to a window containing a frameset. See the top and parent properties.
Because the existence of the current window is assumed, you do not have to reference the name of the window when you call its methods and assign its properties. For example, status="Jump to a new location"
is a valid property assignment, and close()
is a valid method call. However, when you open or close a window within an event handler, you must specify window.open()
or window.close()
instead of simply using open()
or close()
. Due to the scoping of static objects in JavaScript, a call to close()
without specifying an object name is equivalent to document.close()
.
You can reference a window's frame objects in your code by using the frames array. The frames array contains an entry for each frame in a window with a FRAMESET tag.
Windows lack event handlers until some HTML is loaded into them containing a BODY or FRAMESET tag.
Properties
The window object has the following properties:
The following objects are also properties of the window object:
Methods
The window object has the following methods:
Event handlers
Examples
In the following example, the document in the top window opens a second window, window2, and defines pushbuttons that open a message window, write to the message window, close the message window, and close window2. The onLoad and onUnload event handlers of the document loaded into window2 display alerts when the window opens and closes.
win1.html
, which defines the frames for the first window, contains the following code:
<HTML>
<HEAD>
<TITLE>Window object example: Window 1</TITLE>
</HEAD>
<BODY BGCOLOR="antiquewhite">
<SCRIPT>
window2=open("win2.html","secondWindow",
"scrollbars=yes,width=250, height=400")
document.writeln("<B>The first window has no name: "
+ window.name + "</B>")
document.writeln("<BR><B>The second window is named: "
+ window2.name + "</B>")
</SCRIPT>
<FORM NAME="form1">
<P><INPUT TYPE="button" VALUE="Open a message window"
onClick = "window3=window.open('','messageWindow',
'scrollbars=yes,width=175, height=300')">
<P><INPUT TYPE="button" VALUE="Write to the message window"
onClick="window3.document.writeln('Hey there');
window3.document.close()">
<P><INPUT TYPE="button" VALUE="Close the message window"
onClick="window3.close()">
<P><INPUT TYPE="button" VALUE="Close window2"
onClick="window2.close()">
</FORM>
</BODY>
</HTML>
win2.html
, which defines the content for window2, contains the following code:
<HTML>
<HEAD>
<TITLE>Window object example: Window 2</TITLE>
</HEAD>
<BODY BGCOLOR="oldlace"
onLoad="alert('Message from ' + window.name + ': Hello, World.')"
onUnload="alert('Message from ' + window.name + ': I'm closing')">
<B>Some numbers</B>
<UL><LI>one
<LI>two
<LI>three
<LI>four</UL>
</BODY>
</HTML>
See also the example for the frame object.
See also
document, frame objects
window property
Property. The window property is a synonym for the current window or frame.
Syntax
1. window.propertyName
2. window.methodName
Parameters
propertyName is the defaultStatus, status, length, or name property when the calling window refers to a window object.
propertyName is the length or name property when the calling window refers to a frame object.
methodName is any method associated with the window object.
Property of
frame object, window object
Description
The window property refers to the current window or frame.
Although you can use the window property as a synonym for the current frame, your code is more readable if you use the self property. For example, window.name
and self.name
both specify the name of the current frame, but self.name
is easier to understand.
Use the window property to disambiguate a property of the window object from a form or form element of the same name. You can also use the window property to make your code more readable.
The window property is read-only. The value of the window property is
<object nameAttribute>
where nameAttribute is the NAME attribute if window refers to a frame, or an internal reference if window refers to a window.
Examples
In the following example, window.status
is used to set the status property of the current window. This usage disambiguates the status property of the current window from a form called "status" within the current window.
<A HREF=""
onClick="this.href=pickRandomURL()"
onMouseOver="window.status='Pick a random URL' ; return true">
Go!</A>
See also
self property
write
Method. Writes one or more HTML expressions to a document in the specified window.
Syntax
document.write(expression1 [,expression2], ...[,expressionN])
Parameters
expression1 through expressionN are any JavaScript expressions or the properties of existing objects.
Method of
document
Description
The write method displays any number of expressions in a document window. You can specify any JavaScript expression with the write method, including numerics, strings, or logicals.
The write method is the same as the writeln method, except the write method does not append a newline character to the end of the output.
Use the write method within any SCRIPT tag or within an event handler. Event handlers execute after the original document closes, so the write method will implicitly open a new document of mimeType text/html
if you do not explicitly issue a document.open()
method in the event handler.
Examples
In the following example, the write method takes several arguments, including strings, a numeric, and a variable:
var mystery = "world"
// Displays Hello world testing 123
msgWindow.document.write("Hello ", mystery, " testing ", 123)
In the following example, the write method takes two arguments. The first argument is an assignment expression, and the second argument is a string literal.
//Displays Hello world...
msgWindow.
In the following example, the write method takes a single argument that is a conditional expression. If the value of the variable age is less than eighteen, the method displays "Minor." If the value of age is greater than or equal to eighteen, the method displays "Adult."
document.write
(mystr = "Hello " + "world...")
msgWindow.document.write(status = (age >= 18) ? "Adult" : "Minor")
See also
clear, close (document object), open (document object), writeln methods
writeln
Method. Writes one or more HTML expressions to a document in the specified window and follows them with a newline character.
Syntax
document.writeln(expression1 [,expression2], ...[,expressionN])
Parameters
expression1 through expressionN are any JavaScript expressions or the properties of existing objects.
Method of
document
Description
The writeln method displays any number of expressions in a document window. You can specify any JavaScript expression, including numerics, strings, or logicals.
The writeln method is the same as the write method, except the writeln method appends a newline character to the end of the output. HTML ignores the newline character, except within certain tags such as PRE.
Use the writeln method within any SCRIPT tag or within an event handler. Event handlers execute after the original document closes, so the writeln method will implicitly open a new document of mimeType text/html
if you do not explicitly issue a document.open()
method in the event handler.
Examples
All the examples used for the write method are also valid with the writeln method.
See also
clear, close (document object), open (document object), write methods