function updateChecked(boxes) {
	
	var field = document.getElementsByName(boxes);
	var allChecked = document.getElementById("allChecked");
	
	if( allChecked.checked == true ) {

		for (i = 0; i < field.length; i++) {
			field[i].checked = true;
		}
		
	} else if (allChecked.checked == false) {
		
		for (i = 0; i < field.length; i++) {
			field[i].checked = false ;
		}
	}

}