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Adding options

If you don’t load any options into a list box or combo box using HTML, you can do so using JavaScript.

To start, define a method with three arguments: the list box to work on, the name of the option to add,

and the value of the option to add.

ListUtil.add = function (oListbox, sName, sValue) {

//...

}

Next, create an

element using the DOM methods and assign the option name by creating a

text node:

ListUtil.add = function (oListbox, sName, sValue) {

var oOption = document.createElement(“option”);

oOption.appendChild(document.createTextNode(sName));

//...

}

The option value is actually not required, so you should only add it if the argument has been passed in.

To do this, ensure that

arguments.length

is equal to 3, and if so, set the

value

attribute:

ListUtil.add = function (oListbox, sName, sValue) {

var oOption = document.createElement(“option”);

oOption.appendChild(document.createTextNode(sName));

if (arguments.length == 3) {

oOption.setAttribute(“value”, sValue);

}

//...

}

The last step is to add the new option to the list box by using the

appendChild()

method:

ListUtil.add = function (oListbox, sName, sValue) {

var oOption = document.createElement(“option”);

oOption.appendChild(document.createTextNode(sName));

if (arguments.length == 3) {

Even though intended for multiple-selection list boxes, the

getSelectedIndexes()

method works in both single-selection list boxes and combo boxes, returning an

array with only one item: the value of

selectedIndex

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Forms and Data Integrity

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