/*
 * Delete all options in select element
 */
function clearOptions(select_name)
{
    var elSel = document.getElementById(select_name);
    elSel.options.length = 0;
}

/*
 * Add option in select element
 */
function addOption(select_name, item_value, item_text)
{
    var elSel = document.getElementById(select_name);
    var i = elSel.length;
    var opt = new Option(item_text,item_value);
    elSel.options[i] = opt;
}

/*
 * Get current value in select element
 */
function GetSelectControlValue(select_name)
{
    var elSel = document.getElementById(select_name);
    return elSel.options[elSel.selectedIndex].value
}