Jquery add / remove multiple attribute on select

Question

I want to change whether a user can select only, one or multiple options in a select box based on a tick box above. i.e. if the tick box is ticked the user can select multiple values, if not ticked they can only select one value. What is the best way to do this using jquery?

Answer 1

$('#checkboxid').change(function(){
    if ($(this).is(':checked')) {
        $('#listbox').attr('multiple','multiple');
    } else {
        $('#listbox').removeAttr('multiple');
    }
})

Demo: http://jsfiddle.net/ynhat/WCPue/1/