Can anybody help with javascript

Hello,
I am trying to do a hidden field that pops up when you select "other" from a drop down menu. I can make the field disappear but I can't make it pop up when other is selected. I don't have trouble with this using radio buttons but that isn't what the want. Here is my code.

<SCRIPT LANGUAGE=JAVASCRIPT TYPE="TEXT/JAVASCRIPT">
function HideFields() {
document.all["tblOther"].style.display='none';
}
function txtOther() {
var otherfunc=other();
if (otherfunc=="Other") {
document.all["tblOther"].style.visibility='visible';
document.all["otherFunct"].focus();
}
else {
document.all["tblOther"].style.visibility='hidden';
}
}

</script>'

In the form field I am using this to activate onselect='txtOther();'

Thanks for your help

try style.display = 'block'; rather than visibility