Still not working. Just to be sure I'm understanding you correctly, I'm going to take your code and replace all the list names with either List1 and List2 (The list that would show or hide based on List1 selection).
<select name="List2" id="List2" multiple style="display:none">
add the on change to the List1 list:
<select name="List1" onchange="toggleList2(this.options[this.selectedIndex].value);">
and add the funcitn to the head:
<
script type="text/javascript">
function toggleList2(selection) {
var List2List = document.getElementById("List2");
if(selection == "weeks") {
List2List.style.display = "block";
} else {
List2List.style.display = "none";
}
}
</script>
Does this look right?