Textarea

创建源

To define a text area, use standard HTML语法 with the addition of JavaScript event handlers.

事件句柄

• onBlur
• onChange
• onFocus
• onKeyDown
• onKeyPress
• onKeyUp
• onSelect

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. Although this character varies from platform to platform (Unix is \n, Windows is \r, and Macintosh is \n), JavaScript checks for all newline characters before setting a string-valued property and translates them as needed for the user's platform. You could also enter a newline character programmatically--one way is to test the navigator.appVersion property to determine the current platform, then set the newline character accordingly. See navigator.appVersion for an example.

属性概览

方法概览

示例

<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> 示例 2. The following example creates a string variable containing newline characters for different platforms. When the user clicks the button, the Textarea object is populated with the value from the string variable. The result is three lines of text in the Textarea object.

<SCRIPT>
myString="This is line one.\nThis is line two.\rThis is line three."
</SCRIPT>
<FORM NAME="form1">
<INPUT TYPE="button" Value="Populate the textarea"
onClick="document.form1.textarea1.value=myString">
   <P>
<TEXTAREA NAME="textarea1" ROWS=6 COLS=55></TEXTAREA>

参看

属性

安全性

描述

You can set the defaultValue property at any time. The display of the related object does not update when you set the defaultValue property, only when you set the value property.

示例

function defaultGetter() {
   msgWindow=window.open("")
   msgWindow.document.write("hidden.defaultValue is " +
      document.surfCity.hiddenObj.defaultValue + "<BR>")
   msgWindow.document.write("password.defaultValue is " +
      document.surfCity.passwordObj.defaultValue + "<BR>")
   msgWindow.document.write("text.defaultValue is " +
      document.surfCity.textObj.defaultValue + "<BR>")
   msgWindow.document.write("textarea.defaultValue is " +
      document.surfCity.textareaObj.defaultValue + "<BR>")
   msgWindow.document.close()
}

参看

form

描述

示例

function showElements(theForm) {
   str = "Form Elements of form " + theForm.name + ": \n "
   for (i = 0; i < theForm.length; i++)
      str += theForm.elements[i].name + "\n"
   alert(str)
}
</script>
<FORM NAME="myForm">
Form name:<INPUT TYPE="textarea" NAME="text1" VALUE="Beluga">
<P>
<INPUT NAME="button1" TYPE="button" VALUE="Show Form Name"
   onClick="this.form.text1.value=this.form.name">
<INPUT NAME="button2" TYPE="button" VALUE="Show Form Elements"
   onClick="showElements(this.form)">
</FORM> The alert dialog box displays the following text:

JavaScript Alert:
Form Elements of form myForm:
text1
button1
button2 示例 2. The following example uses an object reference, rather than the this keyword, to refer to a form. The code returns a reference to myForm, which is a form containing myTextareaObject.

document.myForm.myTextareaObject.form

参看

name

安全性

描述

If multiple objects on the same form have the same NAME attribute, an array of the given name is created automatically. Each element in the array represents an individual Form object. Elements are indexed in source order starting at 0. For example, if two Text elements and a Textarea element on the same form have their NAME attribute set to "myField", an array with the elements myField[0], myField[1], and myField[2] is created. You need to be aware of this situation in your code and know whether myField refers to a single element or to an array of elements.

示例

newWindow=window.open("http://home.netscape.com") function valueGetter() {
   var msgWindow=window.open("")
   for (var i = 0; i < newWindow.document.valueTest.elements.length; i++) {
      msgWindow.document.write(newWindow.document.valueTest.elements[i].name + "<BR>")
   }
}

type

示例

for (var i = 0; i < document.form1.elements.length; i++) {
   document.writeln("<BR>type is " + document.form1.elements[i].type)
}

value

安全性

描述

You can set the value property at any time. The display of the Textarea object updates immediately when you set the value property.

示例

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("blurb.value is " +
      document.valueTest.blurb.value + "<BR>")
   msgWindow.document.close()
} This example displays the following:

submitButton.value is Query Submit
resetButton.value is Reset
blurb.value is Tropical waters contain all sorts of cool fish,
such as the harlequin ghost pipefish, dragonet, and cuttlefish.
A cuttlefish looks much like a football wearing a tutu and a mop. The previous example assumes the buttons have been defined as follows:

<INPUT TYPE="submit" NAME="submitButton">
<INPUT TYPE="reset" NAME="resetButton">
<TEXTAREA NAME="blurb" rows=3 cols=60>
Tropical waters contain all sorts of cool fish,
such as the harlequin ghost pipefish, dragonet, and cuttlefish.
A cuttlefish looks much like a football wearing a tutu and a mop.
</TEXTAREA>

参看

方法

语法

示例

userText.blur() This example assumes that the textarea is defined as

<TEXTAREA NAME="userText">
Initial text for the text area.
</TEXTAREA>

参看

focus

语法

描述

参看

示例

handleEvent

语法

描述

select

语法

描述

示例

<FORM NAME="myForm">
<B>Last name: </B><INPUT TYPE="text" NAME="lastName" SIZE=20 VALUE="Pigman">
<BR><B>First name: </B><INPUT TYPE="text" NAME="firstName" SIZE=20 VALUE="Victoria">
<BR><B>Description:</B>
<BR><TEXTAREA NAME="desc" ROWS=3 COLS=40>An avid scuba diver.</TEXTAREA>
<BR><BR>
<INPUT TYPE="button" VALUE="Change描述"
   onClick="this.form.desc.select();this.form.desc.focus();">
</FORM>

参看