January 18, 2000 - The Option Constructor | WebReference

January 18, 2000 - The Option Constructor

Yehuda Shiran January 18, 2000
The Option Constructor
Tips: January 2000

Yehuda Shiran, Ph.D.
Doc JavaScript

The Option object is contained by the Select object. The Select object may have many options. They are contained in its options[] array. Here is an example for a reference to an option:

document.forms[3].elements[2].options[5]

The option objects can be create dynamically at runtime, via the Option constructor. The syntax for creating an option is as follows:

var optionObj = new Option([optionText, optionValue, defaultSelected, selected]);

where:

optionText is a string representing the option's text property
  • optionValue is a string representing the option's value property
  • defaultSelected is a string representing the option's defaultSelected property
  • selected is a string representing the option's selected property

    You can add an option to an existing select object in the following fashion:

    selectman.options[index] = optionObj;

    After you create an option and add it to a Select object, you must refresh the document. One way to refresh the document is by using the following JavaScript statement:

    history.go(0)

    You can also delete an option from a Select object, by assigning it a null value. The general syntax will then be:

    selectName.options[index] = null;