如何防止在移动Safari浏览器默认双击行为(缩放,平移)上的iOS4？

document.addEventListener('DOMContentLoaded', function() {
  var lastTouchTime = 0;
  document.addEventListener('touchstart', function(event) {
    if (event.touches.length > 1) {
      event.preventDefault();
    }
  });
  document.addEventListener('touchend', function(event) {
    var currentTime = new Date().getTime();
    var tapDelay = 500; // 延迟时间
    if (currentTime - lastTouchTime < tapDelay) {
      event.preventDefault();
    }
    lastTouchTime = currentTime;
  });
});

body {
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}

<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no">