Ajax history on IE6/7 is broken

I'm programming my own Ajax history library in JS. I ran into problems with IE6 and IE7. Can someone elaborate on why the following is happening?

IE6 & 7

I am able to set the hash values without refreshing the page.

window.location = 'site.com/index.html#' + pageNumber;

I can go to page 1, page 2, page 3, and so on. When I'm on page 3 and hit the back button, I'm not transported back to page 2. Rather, I get completely taken out of开发者_JAVA技巧 index.html! It seems like IE does not think that different hash values are different points in history.

IE7

IE8 in IE7 backwards compatibility mode claims that it has the onhashchange listener.

if ('onhashchange' in window) {
   // true in IE7
   window.onhashchange = someFunction();
}

However, IE7 never executes someFunction() when the URL changes. This implies that it lies about having onhashchange but never implemented it.

Have you try this: http://tkyk.github.com/jquery-history-plugin/

IE6 and IE7 are known to not support the hashchange event; it looks like you found a bug (?) in the IE7 compatibility mode of IE8.

You need to use a library, like the one in Phong Nguyen's answer, to emulate hashchange support via hidden iframes if you want to use this capability in those browsers. In many cases such libraries will also fix your back button problem; I know the one he linked to does.