var lastTouchEnd=0;
document.addEventListener('touchstart',function (event) {
if(event.touches.length>1){
event.preventDefault();
}
});
document.addEventListener('touchend',function (event) {
var now=(new Date()).getTime();
if(now-lastTouchEnd<=300){
event.preventDefault();
}
lastTouchEnd=now;
},false);
document.addEventListener('gesturestart', function (event) {
event.preventDefault();
});