XMLHttpRequest - Troubles with a cross domain API call

I need to do a very simple cross domain api call, and for reasons of overhead/compatibility, dont want to use a fully-featured framework (such a jQuery), since this simple ajax request is pretty much all I need to do. I need to call do a GET request on http://bar.com from a page on http://foo.com. I cannot access the HTTP headers on foo.com however. I do not need to return data to the browser.

Currently doing the center code hereall results in (on Chrome):

XMLHttpRequest cannot load http://bar.com/api?=x. 
Origin http://foo.com is not allowed by Access-Control-Allow-Origin. 
http://bar.com/api?=x Failed to load resource

Incidentally, even though this call throws an error, it comes through fine on bar.com, so another option is basically just catching t开发者_C百科hat error and ignoring it(?). Somewhat unfamiliar with JS though, so not sure if this will fail on other browsers?

Came across this: http://code.google.com/p/xmlhttprequest/source/browse/trunk/source/XMLHttpRequest.js - not sure if this is completely overkill for my use (overhead is pretty critical)?

---

Yes, this will always fail unless you have set the Access-Control-Allow-Origin HTTP header to define specific domains which are allowed to be accessed via XHR.

One way you could work around this issue is by using script injection:

function load_script(loc) {
   var s = document.createElement('script');
   s.src = loc;
   document.getElementsByTagName('head')[0].appendChild(s);
}

load_script('http://bar.com/api?=x');