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                <div class="box"></div>


                .box {
  width: 100px;
  height: 100px;
  background: gray;
  /* 禁用移动端长按弹出系统默认菜单(没啥用) */
/* 	-webkit-touch-callout: none !important;
	-webkit-user-select: none !important;
	user-select: none !important; */


                let box = document.querySelector('.box');

// 没啥用
// box.addEventListener('contextmenu', e => {
//   e.preventDefault();
// }, false);

// 直接绑定,可以阻止弹出系统菜单
box.addEventListener('touchstart', e => {
}, false);

// 事件委派,无法阻止弹出系统菜单
// window.addEventListener('touchstart', e => {
//   if ( === box) {
//     e.preventDefault();
//   }
// });

// box.addEventListener('touchend', e => {
//   e.preventDefault();
// }, false);