While writing a tiny test application today I noticed that Chrome wasn’t displaying my 404 page.

I found out that by default Chrome will try to provide suggestions when it comes across such a navigational error.

If this feature is so good, why is Google’s 404 page displayed differently? More importantly for me today though, why is their 404 page working and mine is not?

The secret is to ensure 512 bytes in your 404 page. If the page is less than 512 bytes, Chrome will display the pre-populated search form.

I’m at a loss why Google think this is a good idea. The behaviour should be consistent for all 404s.