I'm working on a site that will go on my company's intranet. I developed it locally on my computer, checking it in different browsers and on colleague's computers, and when it was done I handed it off to IT. They put identical copies on a staging server, and on the production server. This is a site built only with html, javascript, and css. No server side scripting. It also uses a DWF viewer plugin from Autodesk. It is a single standalone page (not part of a CMS) that allows users to load drawings into the viewer and then click to see info from a database of space info saved in a series of js arrays (the space DB software spits out a js file with all the info listed in array literals, creating a crap ton of global variables - ugh, but I digress).

When I followed their links (using IE 8) the version on the staging server looked as expected, but the layout is hosed on the version from the production server. Specifically, it seems like a div that is supposed to flow to the right of a div that is float: left is displaying below the floated div at full width, as though it was clear: left (which it is not). It also has the wrong height.

I downloaded the files from each and they are identical to my local version. Frustrated, I cleared my browser's cache, restarted my computer, checked it on a colleague's computer who also has IE 8. All the same issue. Staging server good. Production server bad.

Finally I uninstalled IE 8 and looked at it in IE 6. Both versions looked fine.

So, to recap. Two different servers. No server side scripting. Identical files. One browser agrees they are identical, the other does not. What could cause this?