1  var metas = document.getElementsByTagName('meta');
 2  var i;
 3  if (navigator.userAgent.match(/iPhone/i)) {
 4    for (i=0; i<metas.length; i++) {
 5      if (metas[i].name == "viewport") {
 6        metas[i].content = "width=device-width, minimum-scale=1.0, maximum-scale=1.0";
 7      }
 8    }
 9    document.addEventListener("gesturestart", gestureStart, false);
10  }
11  function gestureStart() {
12    for (i=0; i<metas.length; i++) {
13      if (metas[i].name == "viewport") {
14        metas[i].content = "width=device-width, minimum-scale=0.25, maximum-scale=1.6";
15      }
16    }
17  }