How to get information in javascript?(object c + UIWebView + AJAX)

I've already known that there is an interface in UIWebView for object c to call javascript. And now I have a problem: After the javascript is finished, there are some result in the javascript, and I want to get it out and use it with object c. Is it possible to get the result from javascript?

From stackoverflow

• UIWebView's stringByEvaluatingJavaScriptFromString: returns the result of running a script.

  Void.Tan : Thanks. I've just realized this.