As you say, the page looks OK without the form. As soon as this shows with the javascript everything else is forced down. This is because you haven't designed a space for it. You need to redesign the page leaving a space for the form.
If you gave the form a position: absolute attribute all the other parts of the page would show where they should, but the form would overlap them because it has no allocated space.
Add this <div>...</div> in before and after the script:-
<div style="position: absolute; top: 120px; left: 70px;">
<script...........
.............</script>
</div>
and the page will show correctly with the form, but there is no space for it so it covers other content.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.