window.onload = function() {

 	document.addEventListener('touchstart', function(event) {
 		if (event.touches.length > 1) {
 			event.preventDefault();
 		}

 	});

 	document.addEventListener('gesturestart', function(event) {
 		event.preventDefault();
 	});
 };



 // 禁用双指放大
 document.documentElement.addEventListener('touchstart', function(event) {
 	if (event.touches.length > 1) {
 		event.preventDefault();
 	}
 }, {
 	passive: false
 });

 // 禁用双击放大
 var lastTouchEnd = 0;
 document.documentElement.addEventListener('touchend', function(event) {
 	var now = Date.now();
 	if (now - lastTouchEnd <= 300) {
 		event.preventDefault();
 	}
 	lastTouchEnd = now;
 }, {
 	passive: false
 });