I am using Firefox 6 and was initially unable to see the elevation chart once the new version of the site was released, however it did work in Chrome. It appears that the script for the elevation was being blocked by AdBlock Plus along with the ads at the bottom of the screen. When I disabled ad block plus (or more specifically blocking of the necessary script) the elevation data reappeared. This does cause a reduction in the size of the map shown in the brower window.
I'm having the same problem. How do I disable ad block plus for only the necessary script?