XMLHttpRequest Security errors

Hey /prog/, not a regular but I thought I'd try you guys - I'm running into problems when I try to load cross-board content using xmlhttprequest. Apparently it only works in the same domain, so I get security errors when a link pointing to img wants to load content from dat (the cross-board links send you to a redirecting page which does this). Any ideas on how to work through this? I'm running the code through the Greasemonkey Firefox extension. Thanks!

You can modify Firefox' settings to enable cross-domain XHR (prefs.js I guess?). However, you would have to convince others to do so as well to use your script, and I'd like to see the gullibledumb fuck who would. You're opening up your browser for a wide range of XSS exploits by doing so, after all.