Multiselect that only allows single selection

Question

Good afternoon,
I have two multiselect lists on a page. I need to modify the second list so that <ctrl> and <shift> clicking is disabled, and only one item can be selected at a time. Can this be done?
I understand it would function better as a select dropdown list, but my customer prefers the look of the multiselect.
Thanks,
Aaron

Answer 1

Try this (this assumes your multi-select is called P21_MS)
http://apex.oracle.com/pls/otn/f?p=20569:21
HTML Header:
<script type="text/javascript">
function check(){
  var list=$x('P21_MS');
  var count = 0;
    for (i=0; i<list.options.length; i++) {
      if (list.options.selected) {
count++;
if (count > 1){
//clear box
for (i=0; i<list.options.length; i++) {
list.options[i].selected = false;
alert('You may only select 1 option');
</script>
HTML Form Element Options for P21_MS:
onchange="check();"Keep in mind that Javascript can be disabled, so if there is a business rule attached to not selecting more than 1, include a regular Apex validation that does the same check.