Is it safe to use $.support.cors = true; in jQuery?

Question

I was trying to hit a web service on a different domain using jQuery\'s ajax method. After doing some research it looks like it does not allow this is by design to prevent

Answer 1

When a hacker is able to inject script code to change the requests to another domain, he is also able to set this javascript flag in the script.

So wether this flag is set doesn't change much at this point of the intrusion.