Javascript Code for Check/Uncheck all Checkboxes

<script language="javascript">

function checkAll(formname, checktoggle)
{
var checkboxes = new Array();
checkboxes = document[formname].getElementsByTagName('input');
for (var i=0; i<checkboxes.length; i++) {
if (checkboxes[i].type == 'checkbox') {
checkboxes[i].checked = checktoggle;
}
}
}

</script>