Javascript [Electronic resources] : The Definitive Guide (4th Edition) نسخه متنی

Availability

JavaScript 1.0; enhanced in JavaScript
1.1

Inherits from/Overrides

Inherits from Input, HTMLElement

Synopsis

form.name
form.elements[i]

Properties

Textarea inherits the properties of Input and HTMLElement and defines
or overrides the following:

value

A read/write string property. The initial value of this property is
the same as the defaultValue property: the plain
text (i.e., without any HTML tags) that appears between the
<textarea> and
</textarea> tags. When the user types
characters into the Textarea object, the value
property is updated to match the user's input. If you set the
value property explicitly, the string you specify
is displayed in the Textarea object. This value
property contains the string that is sent to the server when the form
is submitted.

Methods

Textarea inherits the methods of Input and HTMLElement.

Event Handlers

Textarea inherits the event handlers of Input and HTMLElement and
defines or overrides the following:

onchange

Invoked when the user changes the value in the Textarea element and
moves the keyboard focus elsewhere. This event handler is not invoked
for every keystroke in the Textarea element, but only when the user
completes an edit.

HTML Syntax

A Textarea element is created with
standard HTML <textarea> and
</textarea> tags:

<form>
...
<textarea
[ name="name" ]         // A name that can be used to refer to this element
[ rows="integer" ]      // How many lines tall the element is
[ cols="integer" ]      // How many characters wide the element is
[ onchange="handler" ]  // The onchange(  ) event handler
>
plain_text              // The initial text; specifies defaultValue
</textarea>
...
</form>

Description

The Textarea element represents a text input field in a form. The
name attribute specifies a name for the element.
This is mandatory if the form is to be submitted, and it also
provides a convenient way to refer to the Textarea element from
JavaScript code. The cols attribute specifies the
width, in characters, of the element as it appears on the screen, and
the rows attribute specifies the height, in lines
of text, of the element. The wrap attribute
specifies how long lines should be handled: the value
off specifies that they should be left as-is, the
value virtual specifies that they should be
displayed with line breaks but transmitted without them, and the
value physical specifies that they should be
displayed and transmitted with line breaks inserted.

In addition to these HTML attributes, value is the
main property of interest for the Textarea element. You can read this
property to obtain the user's input or set it to display
arbitrary (unformatted) text in the Textarea. The initial value of
the value property (and the permanent value of the
defaultValue property) is the text that appears
between the <textarea> and
</textarea> tags.

Note that the Textarea object is a kind of Input object and inherits
from Input, despite the fact that Textarea objects are not created
with HTML <input> tags.

Usage

If you need only a single line of input text, use the Text element.
If the text to be input is sensitive information, such as a password,
use the Password element.

See Also

Form, HTMLElement, Input, Password, Text; HTMLTextAreaElement in the
DOM reference section