Calculate element height the way slideDown() does
<p>Have you noticed that by using jquery's slideDown(), even on elements with dynamic content, you always get the perfect height of the effected element. Which is, for me at least, impossible to do by simply animating the css height value. Mostly because there is no way for me to know how did the height of an element (with a display:none) changed, during a dynamic content (AJAX) update.</p>

<p>And since i've been working on some custom controls, i do need that capability to calculate things the way slideDown() does.</p>
