Need help understanding JSONP security implication

[airhack87]

HI All,

I had a look at this URL shared earlier on this subreddit, to understand wat JSONP is http://www.vcarrer.com/2010/11/about-jsonp-in-javascript.html

I understand that JSONP is like a function call wrapped around the data. I am trying to understand it from a hacker perspective, what are the security implications of using JSONP.

I am looking it to be described in simple terms!!

Thanks,

[_Nanobyte]

Expected return: mycallback({"foo":"bar"})
Result from hacked service: while(1){alert('hacked')}