Drag and drop lagging
<p>As part of a school project, I have DIVs that I need to be able to move. I have it working, and it works perfectly in Firefox. However, in other browsers, it doesn't really work that well. In IE9, it doesn't work at all. In Safari, it lags, even when only one div is up. In Opera and Chrome, it works fine when there's only one div, but if there are several divs on top of each other, and I try to move one over the others, it lags.</p>

<p>I've been going at it for a while, and I've really run out of ideas as to what could cause it.</p>

<p>As this is for school, we're not allowed to use any libraries (as this would have simplified it quite a bit).</p>

<p>The code for making divs draggable is here: <a href="http://pastebin.com/4TGRg1AW" rel="nofollow">http://pastebin.com/4TGRg1AW</a></p>
