// Enforce only two compare boxes being checked at once.function enforceOnlyTwoChecked(clickedCheckbox) {count = 0;first = null;form = clickedCheckbox.form;for (i = 0; i < form.elements.length; i++) {if (form.elements[i].type == 'checkbox' && form.elements[i].checked) {if (first == null && form.elements[i] != clickedCheckbox) {first = form.elements[i];}count += 1;}}if (count > 2) {first.checked = false;count -= 1;}}