CODE EXAMPLE FOR JAVASCRIPT

when i click on one checkbox check all checkboxes

<p><input onClick="setAllCheckboxes('actors', this);" type="checkbox" />All of them</p>
<div id="actors">
    <p><input type="checkbox" name="kevin" />Spacey, Kevin</p>
    <p><input type="checkbox" name="colin" />Firth, Colin</p>
    <p><input type="checkbox" name="scarlett" />Johansson, Scarlett</p>
</div>