function check_change() {
	thisdoc = document.form1;
	thislength = thisdoc.length;
	for (i=0; i < thislength; i++) {
		if (thisdoc.elements[i].type == 'checkbox') {
			if (thisdoc.selAll.checked == true) {
				thisdoc.elements[i].checked = true;
			}
			else {
				thisdoc.elements[i].checked = false;
			}
		}
	}
}