JS is no longer slower than Safari since 8.0, if you use a WKWebView
http://9to5mac.com/2014/06/03/ios-8-webkit-changes-finally-a...
http://9to5mac.com/2014/06/03/ios-8-webkit-changes-finally-a...
https://www.quora.com/Why-doesnt-the-new-Chrome-for-iOS-use-...