ios10兼容问题

var lastTouchEnd = 0;
		document.addEventListener('touchend', function(event) {
			var now = (new Date()).getTime();
			if(now - lastTouchEnd <= 300) {
				event.preventDefault();
			}
			lastTouchEnd = now;
		}, false)
//ios10以上兼容性禁止网页缩放