You mean zooming on the browser screen? That's easy with two fingers swiping in, out.

 

Like jinwons said: Two fingers in like a pinching and un-pinching motion. Like on the *coffs "ipod" to zoom in and out.

 

Or you can double tap the screen for a quick zoom. Also when to touch the screen once you'll notice a plus and minus appear in the bottom right hand corner. This is also for zooming.