I use the js library select2. This is a screenshot of what I have now:
Start:
In my case, I wanted the user's selections from the dropdown to appear in a list below the dropdown, rather than working like a regular dropdown list. So this workaround worked for me:
$('#myselect').select2({
multiple:true
})
.on('select2:select', function (e) {
//clear the input box after a selection is made
$(this).val([]).trigger('change');
});
Of course that won't work if you want the selected item to stay selected in select2's input box like it does with a regular select2 multiselect list.