Forget what I said before; we have a winner!

It’s a given that anything I post here is going to be brain-deflatingly stupid. But this one goes beyond even what I would have expected of Microsoft. Fortunately, thanks to a highly effective Google search, I was able to solve the problem in minutes.

The problem was this: For a site I’m working on, we are manipulating the 404 error feature to allow users to set up customized URLs. If the URL entered doesn’t match a real page, it gets fed into this 404 error script, which looks up the path in a database and redirects the user to their customized page. A bit of a hack, but it’s pretty slick.

As usual, I am developing the site using Firefox as my test browser. But… UH-OH! Surprise! When giving a demo of this feature today using Internet Explorer, we discovered it didn’t work! Internet Explorer was not returning the server’s 404 error page, instead using its own internal version (which we’ve all seen and most generally ignore).

Drat! What to do? Well, as it turns out (thanks to the aforementioned Google search), the problem is quite simple. To quote the unbelievable but, as I verified, 100% accurate description I found on this page:

Internet Explorer has a lightly-documented “feature” that stops it from serving any custom 404 error page that is less than 512 bytes long. Your visitors will instead be sent to IE’s own 404 page, which is generic and suggests they use an MSN search to “look for information on the Internet.” That’s one way to lose visitors! Make sure your custom 404 error page is over this limit — about 10 full lines of text and HTML should be enough.

Yep, that’s it. I did my best Bart Simpson-at-the-blackboard impersonation, filling my 404.html file with a large comment block wherein I repeated (about 130 times, for good measure) the phrase “This block exists solely to force Internet Explorer to load this page.”

Sure enough, it worked. D’oh!

Thinking a bit more about this, I at least think I understand why Microsoft chose to do this. “If the server’s default 404 error page is so short,” I imagine them musing, “then it probably doesn’t offer users much helpful information. And since our wonderful web browser is much more important to our users than the web pages themselves, let’s just butt in and do things our way. (Is there really any other way anyway?)”