We have an ASP app that’s sitting in an iframe on a page which creates a phone directory of our employees. You can see it here:
http://www.cecil.edu/Directory/
The iframe this is sitting in is set to 6350px high. When you click on a letter link in the alphabet, it’s supposed to jump down to that letter on the page. It only seems to work properly in Chrome and Safari. No dice with IE 7/8/9 or Firefox.
This used to work fine before, at least in IE8, but stopped working at some point. Doing some fiddling, I found that the anchor tags would work if I dropped the height of the iframe down to around 4000px. But anything above that makes them either behave oddly by taking you to the wrong position on the page or not working at all.
Does anyone have knowledge of large iframe heights causing weird behavior like this? I can’t seem to find any reference to it anywhere online.
When IE uses Direct-X to render objects (such as when using css filter:), no dimension can be larger than 4906 pixels in any axis, due to the max size of a 12-bit register. While this may be an explanation for the limit in IE, it does not explain the limit in Firefox.
See: IE display transparency bug on height > 4096px?