Webmaster in a Nutshell, 3rd Edition By Robert Eckstein, Stephen Spainhour
Table of Contents
Chapter 11. JavaScript
Select
Client-Side JavaScript 1.0
A graphical selection list
Inherits From: Element
form .elements[ i ] form .elements[ element_name ] form . element_name
Properties
The Select object defines properties for each of the attributes of the HTML <select> tag, such as disabled, multiple, name , and size . In addition, it defines the following properties:
form
The Form object that contains this Select object. Read-only.
length
A read-only integer that specifies the number of elements in the options[ ] array. The value of this property is the same as options.length.
options[ ]
An array of Option objects, each describing one of the options displayed within the Select element. You can shorten the set of options by setting the options.length property to a smaller value (or remove all options by setting it to zero). You can remove individual options by setting an element of the array to nullthis shifts the elements above it down, shortening the array. You can append options to the Select object by using the Option( ) constructor to create a new Option and assigning it to options[options.length].
selectedIndex
A read/write integer that specifies the index of the selected option within the Select object. If no option is selected, selectedIndex is -1. If more than one option is selected, selectedIndex specifies the index of the first one only. Setting this property causes all other options to become deselected. Setting it to -1 causes all options to be deselected.
type
A read-only string property that specifies the type of the element. If the Select object allows only a single selection (i.e., if the multiple attribute does not appear in the object's HTML definition), this property is "select-one". Otherwise, the value is "select-multiple". See also Input.type. JS 1.1.
Methods
add( new , old )
Inserts the Option object new into the options[ ] array at the position immediately before the Option object old . If old is null, the new Option is appended to the array. Returns nothing. DOM Level 1.
blur( )
Yields the keyboard focus and returns nothing.
focus( )
Grabs the keyboard focus and returns nothing.
remove( n )
Removes the n th element from the options[ ] array. Returns nothing. DOM Level 1.
Event Handlers
onblur
Invoked when input focus is lost.
onchange
Invoked when the user selects or deselects an item.
