Scrolling is not smooth

Question

This is my HTML5 mobile app.
http://hn.premii.com/
there are couple of issues:
1. Scrolling is not smooth as other browsers (Chrome, Safari or IE10). on firefox, scrolling shutters. How do I make scrolling smooth as other browsers?
2. When you click on links, it shows gray background. How do I disable that?

Answer 1

I am not creating my own scroll handlers. I am using overflow: auto for scrolling. I have Nexus 4 and galaxy s3, and firefox scrolling shutters on both.
Also removing that CSS won't help at all. Color is for text color, and not background color. You can remove tap highlight color in webkit using
-webkit-tap-highlight-color: rgba(255, 255, 255, 0);
}