[jQuery] Handling BACK button depending on hash value in URL

Hello,

I am trying to handle back button on my page so a function would be
called whenever I press the button. I dynamically set the
"location.hash" value on the page. I was hoping to achieve the
functionality by onBeforeUnload, but it does not react on change of
hash value in url – it just reacts on changing url address.

Is there any other way? For example I am trying to achieve the
functionality like in gmail, when back button pressed.