What can cause a double page request?

Question

I am currently investigating a double request problem on my site. Not all the time, but sometimes, a requested page will in fact load twice...which is not a problem really u

Answer 1

We had a very strange behaviour in our CMS where an iframe in a jQuery dialog lightbox made a doubled database insert. After hours of debugging and loud WTFs we nailed it down. the dialog close method was setting the focus to the iframe of the dialog before destroying it and caused a reload of the iframe url!