Select all / Unselect all in Bootstrap Select plugin

<select id="divRatings" class="selectpicker" multiple title='Choose one of the following...' data-size="5" data-selected-text-format="count>2">
    <option value="All" selected="selected">All Ratings</option>
    <option value="EC">EC (Early Childhood)</option>
    <option value="E">E (Everyone)</option>
    <option value="E10+">E10+ (Everyone 10+)</option>
    <option value="T">T (Teen)</option>
    <option value="M">M (Mature)</option>
    <option value="AO">AO (Adults Only)</option>
</select>

In html above there are option with value All. I want to select all items if that option is selected and unselect all if i unselect this option.

I think it will be simple to do, but i can't get why nothing happens on $('#divRatings').change(function(){//some logic});

My function to select/ unselect items:

function toggleSelectAll(control) {
    if (control.val().indexOf("All,") > -1) {
        control.selectpicker('selectAll');
    } else {
        control.selectpicker('deselectAll');
    }
}

JSFiddle example

Problem with your javascript is that anytime user clicks any option you check, if "All ratings" option is still checked - you check all other options too (even if you just unchecked any option). And if "All ratings" is unchecked, you uncheck all other options. So, in fact only "All ratings" option is clickable. If you click any other option, it's immediatelly checked/unchecked in your onchange handler.

Try this code:

function toggleSelectAll(control) {
    var allOptionIsSelected = (control.val() || []).indexOf("All") > -1;
    function valuesOf(elements) {
        return $.map(elements, function(element) {
            return element.value;
        });
    }

    if (control.data('allOptionIsSelected') != allOptionIsSelected) {
        // User clicked 'All' option
        if (allOptionIsSelected) {
            // Can't use .selectpicker('selectAll') because multiple "change" events will be triggered
            control.selectpicker('val', valuesOf(control.find('option')));
        } else {
            control.selectpicker('val', []);
        }
    } else {
        // User clicked other option
        if (allOptionIsSelected && control.val().length != control.find('option').length) {
            // All options were selected, user deselected one option
            // => unselect 'All' option
            control.selectpicker('val', valuesOf(control.find('option:selected[value!=All]')));
            allOptionIsSelected = false;
        } else if (!allOptionIsSelected && control.val().length == control.find('option').length - 1) {
            // Not all options were selected, user selected all options except 'All' option
            // => select 'All' option too
            control.selectpicker('val', valuesOf(control.find('option')));
            allOptionIsSelected = true;
        }
    }
    control.data('allOptionIsSelected', allOptionIsSelected);
}

$('#divRatings').selectpicker().change(function(){toggleSelectAll($(this));}).trigger('change');

http://jsfiddle.net/bu5vjdk6/4/

Updated code
http://jsfiddle.net/surajkm33/tsomyckj/