Question

Is it possible to do AJAX calls from inside an iframe that has a different domain source?

I’ve tried script injection but it doesn’t work because the iframe’s source is secure.
I made a simple fiddle with California DMV website here.

I’m getting DOM exception 8 error. Is it a security issue?

Answer 1

It is not possible to modify or make JS calls in an iframe with a different domain source. This is restricted in all browsers for security reasons.

See the “Same Origin Policy” for a description of how inter frame security works. In a nutshell, there is very little communication allowed between frames on a different domain for security reasons. You cannot make any direct Javascript calls between frames on different domains.

There is a way to make cross domain ajax calls and it involves using JSONP. Basically, you inject a script tag into your own frame and that script tag points to server endpoint anywhere on the web. Since the src value of a script tag is not restricted by the same origin policy, you can reach that server. But, now you need to have a way to get that result back. That is done using JSONP where you specify in your server request a javascript function that you want the returned javascript to call. That returned javascript can have javascript data in it that is then passed to the desired function. JSONP requires cooperation between both client code and the server code since a normal ajax call might not support the extra part of JSONP. But, with this cooperation of both sides, you can get around the same origin policy for server endpoints that support JSONP.

HTML5 has a new messaging system that can safely communicate data (not direct JS calls) between cooperating frames in different domains. See here and here for a description of how the HTML5 messaging works.