js禁用移动端浏览器双指放大及双击放大

<script>
// 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
 
});

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