javascript手冊-t

The following example specifies that responses to the musicInfo form are displayed in the "msgWindow" window:

document.musicInfo.target="msgWindow"

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For form:

text object

A text input field on an htm form. A text field lets the user enter a word, phrase, or series of numbers.

语法

To define a text object, use standard htm 语法 with the addition of the onBlur, on Change, onFocus, and onSelect event handlers:

<input

   TYPE="text"

   NAME=""

   VALUE="textValue"

   SIZE=integer

   [onBlur="handlerText"]

   [onChange="handlerText"]

   [onFocus="handlerText"]

   [onSelect="handlerText"]>

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)

Property of

描述

A text object on a form looks as follows: <form>

Last name: <input size=25 value=Salamone> </form>

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

Methods

Event handlers

例子

Example 1. The following example creates a text object that is 25 characters long. The text field appears immediately to the right of the words "Last name:". The text field is blank when the form loads.

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 upper case.

相关 the 例子 for the onBlur, onChange, onFocus, and onSelect event handlers.

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text property

A string specifying the text that follows an <option> tag in a select object.

语法

selectName.options[index].text

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

描述

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:

Be careful if you change the text property. If you evaluate the property after you change it, the property contains the new value, not the value that is displayed onscreen.

例子

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

}

<select NAME="musicType">

   <option SELECTED> R&B

   <option> Jazz

   <option> Blues

   <option> New Age

</select>

textarea object

A multiline input field on an htm form. A textarea field lets the user enter words, phrases, or numbers.

语法

To define a text area, use standard htm 语法 with the addition of the onBlur, onChange, onFocus, and onSelect event handlers:

<textarea

   NAME=""

   ROWS="integer"

   COLS="integer"

   WRAP="off|virtual|physical"

   [onBlur="handlerText"]

   [onChange="handlerText"]

   [onFocus="handlerText"]

   [onSelect="handlerText"]>

   textToDisplay

</textarea>

The WRAP attribute controls word wrapping inside the TEXTAREA. The value "off" is default and lines are sent exactly as typed. The value "virtual" wraps in the display but are sent exactly as typed. The value "physical" wraps in the display and sends new-lines at the wrap points as if new-lines had been entered.

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)

Property of

描述

A textarea object on a form looks as follows: <form>

<textarea cols=45 name=item_描述 rows=5>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> </form>

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 \r\n, and Macintosh is \n. One way to enter a newline character programatically 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

Methods

Event handlers

例子

The following example creates a textarea object that is 6 rows long and 55 columns wide. The textarea field appears immediately below the word "描述:". When the form loads, the textarea object contains several lines of data, including one blank line.

相关 the 例子 for the onBlur, onChange, onFocus, and onSelect event handlers.

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title property

A string representing the title of a document.

语法

document.title

Property of

document

描述

The title property is a reflection of the value specified within the tags. If a document does not have a title, the title property is null.

title is a read-only property.

例子

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.

语法

dateObjectName.toGMTString()

dateObjectName is either the name of a date object or a property of an existing object.

用法

Date

描述

The exact format of the value returned by toGMTString varies according to the platform.

例子

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

相关

toLocaleString method

Converts a date to a string, using the current locale's conventions.

语法

dateObjectName.toLocaleString()

dateObjectName is either the name of a date object or a property of an existing object.

用法

Date

描述

例子

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

相关

toLowerCase method

Returns the calling string value converted to lower case.

语法

stringName.toLowerCase()

stringName is any string or a property of an existing object.

用法

string

描述

The toLowerCase method returns the value of stringName converted to lower case. toLowerCase does not affect the value of stringName itself.

例子

The following 例子 both yield "alphabet".

var upperText="ALPHABET"

document.write(upperText.toLowerCase())

"ALPHABET".toLowerCase()

相关

top property

The top property is a synonym for the top-most Navigator window, which is a "document window" or "Web Browser window."

语法

1. top.propertyName

2. top.methodName

3. top.frameName

4. top.frames[index]

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

描述

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