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.