JSAN.use('DOM.Events', 'addListener');

Event.observe(window, 'load', function () {
	Event.observe(document.forms['f1'], 'submit',
		function (e) {
			if (Event.element(e).name == "ProjectIndex") return true;

			var form = document.forms['f1'];
			var selectCount = 0;

			for (i = 0; i < form.length; i++) {
				if (form.elements[i].type == 'select-one') {
					if (form.elements[i].options[
							form.elements[i].selectedIndex
						].value != '') {
						selectCount++;
					}
				}
			}

			if (selectCount != 1) {
				var msg = selectCount == 0
						? "You must select a product first!"
						: "You can only select one product!";

				alert(msg);

				if (e.preventDefault) {
					e.preventDefault();
				}
				else {
					e.returnValue  = false;
				}
				
				return false;
			}
		}
	);
});

addListener(window, 'load',
    function () {
    	for (i = 0; i < document.forms['f1'].length; i++) {
			document.forms['f1'].elements[i].onchange =
				function (objectEvent) {
					if (this.options[this.selectedIndex].value == "") {
						return;
					}

					for (i = 0; i < document.forms['f1'].length; i++) {
						if (   document.forms['f1'].elements[i].type
								== 'select-one'
							&& document.forms['f1'].elements[i]
								!= this
						) {
							document.forms['f1'].elements[i].selectedIndex
								= this;
						}
					}
				};
		}
	}
);