Populate Multiple Text Boxes From A Dropdown (can Populate 1 Text Box)?

Below is the code I use to populate a textboxes (compaddress) when I select the compname from the dropdown. I would like to be able to populate other textboxes such as the compdescription, compmaincontact and others when I select the compname from the dropdown. I think that I need an array but I really would like some advice on how to do it as all of my attempts have failed so far

Code:
<script type="text/javascript">
function showname(what)
{
what.form.textfield.value=what.options[what.selectedIndex].title
}
window.onload=function() {
showname(document.form1.number)
}
[Code]...