Useful Javascript for Select Box population

A couple of little useful Javascript helper functions for populating select boxes. If you've got a significant number of choices to present to the user, or a clear reason to categorise the choices presented (maybe providing the list of major towns to choose from restricted by a previous choice of county/state) dynamically populating/re-populating the select drop-down can make the user experience a lot better. There's also the added bonus that, for a list which could run to several hundreds of items, the download overhead of only bringing back those required, when required, by using a call to the server via the XMLHTTP object is significantly reduced as SELECT -> OPTION elements are quite verbose,

/*
Parameters:

controlID: The HTML ID of the element to populate
itemArray: An aray of arrays (of ) to use to populate the drop down
selectedIndex: [NOT USED] The selectedIndex value to use
*/
function populateDropDown(controlID, itemArray, selectedIndex)
{
var x = document.getElementById(controlID);
var item;
for (i = 0; i < itemArray.length; i++)
{
addOptionToDropDown(x, itemArray[i][0], itemArray[i][1]);
}
}

/*
Parameters:

dropDown: The selectbox DOM object to work on
itemValue: The value for the option.value attribute
itemText: The value for the option.text attribute

Notes:

Called by populateDropDown

*/
function addOptionToDropDown(dropDown, itemValue, itemText)
{
/*
Note: This code is Internet Explorer specific and will require changing if compatibility with other
browsers is needed (See: http://www.w3schools.com/htmldom/met_select_add.asp)
*/
var option = document.createElement('option');
option.id = dropDown.id + '_' + itemValue;
option.value = itemValue;
option.text = itemText;
dropDown.add(option);
}