JavaScript实现鼠标拖拽与右键点击消失功能

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    *{
      margin:0;
      padding:0;
    }
    div{
      width: 100px;
      height: 100px;
      background: blue;
      position: absolute;
    }
  </style>
</head>
<body>
<div>
</div>
<script>
  window.onload=function () {
    var oDiv=document.getElementsByTagName("div")[0];
    oDiv.onmousedown=function () {
      document.onmousemove=function (ev) {
        var event=window.event||ev;
        oDiv.style.left=event.clientX+"px";
        oDiv.style.top=event.clientY+"px";
      }
      document.onmouseup=function (){
        document.onmousemove=null;
        document.onmouseup=null;
      }
    }
  }
</script>
</body>
</html>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <style>
    *{
      margin: 0;
      padding: 0;
    }
    div{
      width: 100px;
      height: 100px;
      background: red;
      display: block;
    }
  </style>
</head>
<body>
<div>
</div>
<script>
  window.onload=function () {
    document.oncontextmenu=function () {
      var oDiv=document.getElementsByTagName("div")[0];
      oDiv.style.display="none"
      return false
    }
  }
</script>
</body>
</html>