Prohibited page zoom on mobile

first step:

<meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0;" name="viewport" />

The second step:

     window.onload = function () {
        document.addEventListener('gesturestart', function (e) {
            e.preventDefault();
        });
        //以上是禁止双指缩放
        //以下是禁止双击缩放
        document.addEventListener('touchstart', function (e) {
            if (e.touches.length > 1) {
                e.preventDefault();
            }
        });
        var endTouch = 0;
        document.addEventListener('touchend', function (e) {
            var nowTouch = (new Date()).getTime();
            if (nowTouch - endTouch<= 300) { //为什么是300，看注意
                e.preventDefault();
            }
            endTouch = nowTouch ;
        }, false);
    };

Note:
Click penetration problem: the mobile terminal click will have a delay of about 300ms than touchstart/touchend. The browser will wait 300ms after the click to determine whether the user clicks multiple times. If there are multiple clicks within 300ms, it will be judged as not a click event.