Remove Options from a Combo Box Using JavaScript
From SmartWiki
You can use a JavaScript function to modify the options available in a pull-down box on the page.
The following example removes two different Types available for new Level 2 records (would be useful if you need to define complex criteria for what type of Level 2 records can be created):
function RemoveTypes() { var i=0; var frm = document.forms[0]; // at Level 1 use document.form1 instead of document.forms[0] if (frm.eventid.value==0) // Note: this loop starts at the bottom to avoid skipping any due to re-indexing as they are removed. for (i=frm.eventtype.options.length-1;i>=0;i--) { if (frm.eventtype.options[i].text=='FirstType' || frm.eventtype.options[i].text=='SecondType') frm.eventtype.options[i]=null; } } } RemoveTypes();