I've got a "super secure" javascript downloader^* that I wrote, and it usually works alright. But I noticed, while trying to download a 90 meg file with it on a client's machine that on IE7, it's getting hung up about 1/3rd of the way through. I've never tried to send a file that large through the iFrame and it works fine in other browsers. Is there a size restriction on files that IE7 can read in an iFrame?

^{* It's really just a PHP line that sets header("location: http://someplace/downloadbigthing.exe"); after it does some logging and verification.}