Question

I have used Jquery Chosen plugin.I have fill up the data dynamically in drop down list.

I have allowed to select multiple option.But my question is that if user select All option then not allowed to select other option.If user remove selection of all then allow.

Jquery Chosen : http://harvesthq.github.com/chosen/

<select id="test" data-placeholder="Select Department..." class="chzn-select" multiple tabindex="6">
    <option value=""></option>  
    <option value="-1">All</option>
    <option value="1">One</option>
    <option value="2">Two</option>
</select>

Answer 1

Well that’s easy .. all you have to do is deselect everything but the All option each time a use selects something… here goes the code:

//first we cache the all option selector
var theAllOption = $('#test option[value="-1"]');
$("#test").on({
    change: function() {
        var element = $(this);
        //if the all option is selected we find all the selected options and deselect them
        if (theAllOption.is(":selected")) {
            element.find("option:selected").not(theAllOption).removeAttr("selected");
        }
    }
});​

A working example can be found here: http://jsfiddle.net/senegalo/EKvUE/3/

A Working Example With Chosen plugin: http://jsfiddle.net/senegalo/EKvUE/4/