Hi, i wander if you can help

is it possible to add items to drop down menu's at runtime? its easy enogh to do when codeing, just a lot of "<options" 's but i cant seem to find a way to do it at run time (i need to do it at runtime and not design time)

i have a feeling it will be somewhere along the lines of

<script>
document.form.menu.options.add
</script>

but i cant get any thing working

thanks in advance
<*Martyn*>