function selectAll(formObj, fieldname) {
	var formvar = eval('formObj.form.'+fieldname)
	var mode = (formObj.value == 'Select all');
	for (var i = 0; i<formvar.length; i++) {
		formvar[i].checked=mode;
	}
	if (mode) {
		formObj.value = 'De-select all';
	} else {
		formObj.value = 'Select all';
	}
}