Select object example

select method

Selects the input area of the specified password, text, or textarea object.

语法

1. passwordName.select()2. textName.select()3. textareaName.select()

passwordName is either the value of the NAME attribute of a password object or an element in the elements array.
textName is either the value of the NAME attribute of a text object or an element in the elements array.
textareaName is either the value of the NAME attribute of a textarea object or an element in the elements array.

方法

password, text, textarea

描述

Use the select method to highlight the input area of a form element. You can use the select method with the focus method to highlight a field and position the cursor for a user response.

例子

In the following example, the checkPassword function confirms that a user has entered a valid password. If the password is not valid, the select method highlights the password field and the focus method returns focus to it so the user can re-enter the password.

function checkPassword(userPass) {   if (badPassword) {      alert(Please enter your password again.)      userPass.focus()      userPass.select()   }}

<INPUT TYPE=password NAME=userPass>

相关

select object (options array)

A selection list or scrolling list on an htm form. A selection list lets the user choose one item from a list. A scrolling list lets the user choose one or more items from a list.

语法

To define a select object, use standard htm 语法 with the addition of the onBlur, onChange, and onFocus event handlers:

<SELECT   NAME=selectName   [SIZE=integer]   [MULTIPLE]   [onBlur=handlerText]   [onChange=handlerText]   [onFocus=handlerText]>   <OPTION VALUE=optionValue [SELECTED]> textToDisplay [ ... <OPTION> textToDisplay]</SELECT>

To use a select objects properties and methods:

1. selectName.propertyName2. selectName.methodName(parameters)3. formName.elements[index].propertyName4. formName.elements[index].methodName(parameters)

To use an options properties:

1. selectName.options[index1].propertyName2. formName.elements[index2].options[index1].propertyName

Property of

描述

A select object on a form looks as follows. The object on the left is a selection list that lets the user choose one item; the object on the right is a scrolling list that lets the user choose one or more items:

A select object is a form element and must be defined within a <FORM> tag.

The options array

You can reference the options of a select object in your code by using the options array. This array contains an entry for each option in a select object (<OPTION> tag) in source order. For example, if a select object named musicStyle contains three options, these options are reflected as musicStyle.options[0], musicStyle.options[1], and musicStyle.options[2].

To use the options array:

1. selectName.options2. selectName.options[index]3. selectName.options.length

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.

To obtain the number of options in a select object, use the length property of either the options array or the select object:

1. selectName.length2. selectName.options.length

The select object has properties that you can access only through the options array. These properties are listed below.

Even though each element in the options array represents a select option, the value of options[index] is always null. The value returned by selectName.options represents the full htm statement for the selectName object.

Elements in the options array are read-only. For example, the statement selectName.options[0]=guitar has no effect.

Properties

The select object has the following properties:

The options array has the following properties:

Methods

Event handlers

例子

Example 1. The following example displays a selection list and a scrolling list.

Example 2. The following example displays two selection lists that let the user choose a month and day. These selection lists are initialized to the current date. The user can change the month and day by using the selection lists or by choosing preset dates from radio buttons. Text fields on the form display the values of the select objects properties and indicate the date chosen and whether it is Cinco de Mayo.

相关 the 例子 for the defaultSelected property.

相关

selected property

A Boolean value specifying the current selection state of an option in a select object.

语法

selectName.options[index].selected

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

If an option in a select object is selected, the value of its selected property is true; other