How to reinitialize the multiSelect to select box

[ranjithphptech]

$(".subModules").html(options1);
$(".subModules").multiSelect()
after adding more than one option via ajax , added option not showing how can reinitialize the select box

for example
working correctly
roleMap.setSubModules(); //setting option to the $(".subModules") element
$(".subModules").multiSelect({
selectableHeader: "

Avilable

",
selectionHeader: "

Selected

",
afterInit:function() {

			},
			afterSelect: function(values) {
				alert("Select value: " + values);
			},
			afterDeselect: function(values) {
				alert("Deselect value: " + values);
			}
		});

** following code not working correctly**

$(".subModules").multiSelect({
selectableHeader: "

Avilable

",
selectionHeader: "

Selected

",
afterInit:function() {

			},
			afterSelect: function(values) {
				alert("Select value: " + values);
			},
			afterDeselect: function(values) {
				alert("Deselect value: " + values);
			}
		});

roleMap.setSubModules(); //setting option to the $(".subModules") element

how can fix this