Sorting dropdown list using Javascript

Question

i want to sort the drop down items using javascript,can anyone tell me how to do this.

Answer 1

FOR DROPDOWN FOR WHOLE PROJECT

$(document).ready(function () {
    $.when($('select').addClass('auto-drop-sort')).then($.fn.sortDropOptions("auto-drop-sort"))
})

/*sort all dropdown*/
$.fn.sortDropOptions = function(dropdown_class){
    var prePrepend = ".";
    if (dropdown_class.match("^.") == ".") prePrepend = "";
    var myParent = $(prePrepend + dropdown_class);
    $.each(myParent, function(index, val) {
        /*if any select tag has this class 'manual-drop-sort' this function wont work for that particular*/
        if ( ! $(val).hasClass('manual-drop-sort') ) {
            var selectedVal = $(val).val()
            $(val).html($(val).find('option').sort(
                function (a, b) {
                    if ( a.value != -1 && a.value != 0 && a.value != '' ) {
                        return a.text == b.text ? 0 : a.text < b.text ? -1 : 1 
                    }
                })
            );
            $(val).val(selectedVal)
        }else{
            /* set custom sort for individual select tag using name/id */
        }
    });
}