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: http://www.arcetri.astro.it/irlab/doc/library/javascript/clientreference/text.htm
Дата изменения: Thu Oct 7 13:13:35 1999 Дата индексирования: Sat Dec 22 14:14:30 2007 Кодировка: Поисковые слова: п п п п п п п п п п |
INPUT
tag, with "text"
as the value of the TYPE
attribute. For a given form, the JavaScript runtime engine creates appropriate Text
objects and puts these objects in the elements
array of the corresponding Form
object. You access a Text
object by indexing this array. You can index the array either by number or, if supplied, by using the value of the NAME
attribute.
To define a Text
object, use standard HTML syntax with the addition of JavaScript event handlers.
Text
object on a form looks as follows:
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
).
Property |
Description
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| |
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Method |
Description
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watch
and unwatch
methods from Object
.
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.
<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">See also the examples for the
<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>
onBlur
, onChange
, onFocus
, and onSelect
.
Text
, Form
, Password
, String
, Textarea
blur()
userText:
userText.blur()This example assumes that the text element is defined as
<INPUT TYPE="text" NAME="userText">
Text.focus
, Text.select
Text
object.defaultValue
reflects the value of the VALUE
attribute. Setting defaultValue
programmatically overrides the initial setting.
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.
defaultValue
property of objects on the surfCity
form and displays the values in the msgWindow
window:
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()
}
Text.value
focus()
focus
method to navigate to a text field and give it focus. You can then either programmatically enter a value in the field or let the user enter a value. If you use this method without the select
method, the cursor is positioned at the beginning of the field.
select
.
Text.blur
, Text.select
form
property that is a reference to the element's parent form. This property is especially useful in event handlers, where you might need to refer to another element on the current form.
myForm
contains a Text
object and a button. When the user clicks the button, the value of the Text
object is set to the form's name. The button's onClick
event handler uses this.form
to refer to the parent form, myForm
.
<FORM NAME="myForm">Example 2. The following example shows a form with several elements. When the user clicks
Form name:<INPUT TYPE="text" NAME="text1" VALUE="Beluga">
<P>
<INPUT NAME="button1" TYPE="button" VALUE="Show Form Name"
onClick="this.form.text1.value=this.form.name">
</FORM>
button2
, the function showElements
displays an alert dialog box containing the names of each element on the form myForm
.
function showElements(theForm) {The alert dialog box displays the following text:
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="text" 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>
JavaScript Alert:Example 3. The following example uses an object reference, rather than the
Form Elements of form myForm:
text1
button1
button2
this
keyword, to refer to a form. The code returns a reference to myForm
, which is a form containing myTextObject
.
document.myForm.myTextObject.form
Form
handleEvent(event)
event | The name of an event for which the specified object has an event handler. |
name
property initially reflects the value of the NAME
attribute. Changing the name
property overrides this setting. The name
property is not displayed on-screen; it is used to refer to the objects programmatically.
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.
valueGetter
function uses a for
loop to iterate over the array of elements on the valueTest
form. The msgWindow
window displays the names of all the elements on the form:
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>")
}
}
select()
select
method to highlight the input area of a text field. You can use the select
method with the focus
method to highlight a field and position the cursor for a user response. This makes it easy for the user to replace all the text in the field.
onClick
event handler to move the focus to a text field and select that field for changing:
<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><BR>
<INPUT TYPE="button" VALUE="Change last name"
onClick="this.form.lastName.select();this.form.lastName.focus();">
</FORM>
Text.blur
, Text.focus
Text
objects, the value of the type
property is "text"
. This property specifies the form element's type. type
property for every element on a form.
for (var i = 0; i < document.form1.elements.length; i++) {
document.writeln("<BR>type is " + document.form1.elements[i].type)
}
VALUE
attribute of the object.value
property is a string that initially reflects the VALUE
attribute. This string is displayed in the text field. 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
object updates immediately when you set the value
property.
value
property of a group of buttons and displays it in the msgWindow
window:
function valueGetter() {This example displays the following:
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("myText.value is " +
document.valueTest.myText.value + "<BR>")
msgWindow.document.close()
}
submitButton.value is Query SubmitThe previous example assumes the buttons have been defined as follows:
resetButton.value is Reset
myText.value is Stonefish are dangerous.
<INPUT TYPE="submit" NAME="submitButton">
<INPUT TYPE="reset" NAME="resetButton">
<INPUT TYPE="text" NAME="myText" VALUE="Stonefish are dangerous.">
Text.defaultValue
Last Updated: 05/28/99 12:00:41