How can an iFrame from another domain get rid of itself?

I am building a bookmarklet for various sites that functions basically like this:

1. User navigates to foo.com (an external site not on my control)
2. User clicks a bookmarklet on his browsers that grabs some information from foo.com and displays it on a form in bar.com inside an iframe
3. User submits the form inside bar.com which is inside foo.com
4. The iframe dissapears

The problem is getting the iFrame 开发者_开发百科to remove itself. Since I can't access a function inside a parent domain in another domain I cannot create a custom function parent.removeIFrame() or even do a window.top.location.reload(). I tried many techniques but all of them fail because of cross domain scriptings.

The way I solved it was to change the top.location.href to a custom page I built at bar.com/back.html in which all it does is simply to send a single "history.back()" command that bounces the user on the original page. Althought creative, I don't think it's very elegant solution. Is there a better way?

You can try fragment identifier for cross domain messaging. There is a YUI library for it: http://www.julienlecomte.net/blog/2007/11/31/

When you injected the JS code to create the form on the site's page you can have it poll (js outside of the newly created iframe) your server to know when to remove the iframe. You can use all kinds of methods of doing this including jsonp, long polling, post message, fragment identifiers, etc. You do not need to load a big library for this - the smaller the better for bookmarklets.