Html5 手机网页中，长按会触发系统事件，请问怎么取消这些事件

在页面中样式中加上下面的css代码

*{

-webkit-overflow-scrolling: touch

-webkit-touch-callout:none

-webkit-user-select:none

-khtml-user-select:none

-moz-user-select:none

-ms-user-select:none

user-select:none

}

<td id="mytd"></td>

<script type="text/javascript">

var tddom= document.getElementById('mytd')

var timer = null

tddom.onmousedown = function(){

timer = setTimeout( doStuff, 2000 )//这里设置时间

}

tddom.onmouseup = function(){

clearTimeout( timer )

}

function doStuff() {

alert('hello, you just pressed the td for two seconds.')

}

</script>

禁止复制

οncοntextmenu='return false'    //禁止右键

οndragstart='return false'    //禁止拖动

onselectstart ='return false'    //禁止选中

οnselect='document.selection.empty()'    //禁止选中

οncοpy='document.selection.empty()'    //禁止复制

onbeforecopy='return false'   // 禁止复制

οnmοuseup='document.selection.empty()'

*{

  moz-user-select: -moz-none

  -moz-user-select: none

  -o-user-select:none

  -khtml-user-select:none

  -webkit-user-select:none

  -ms-user-select:none

  user-select:none

}

长按事件document.addEventListener("touchstart", function (e) {     console.log('touchstart')     timer = setTimeout(function () {         console.log('LongPress')         e.preventDefault()         LongPress(parentObj)     }, 800) }) document.addEventListener("touchmove", function (e) {     console.log('touchmove')     clearTimeout(timer)     timer = 0 }) document.addEventListener("touchend", function (e) {     console.log('touchend')     clearTimeout(timer)     if (timer != 0) {         alert('这是点击，不是长按')     }     return false })

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