Get a content of webpage after javascript is loaded SWIFT

How can I get a content of a webpage with the url, after the javascript has been loaded to the html?

I tried let url = NSURL(string: "http://www.myurl.com/") let html = NSString(contentsOfURL: url!, encoding: NSUTF8StringEncoding, error: &error) but its showing only the source of the html page, because the javascript not loaded yet