禁止鼠标拖动复制以及Ctrl+A

//javascript
<script type="text/javascript">
     function disableSelection(target){
          if (typeof target.onselectstart!="undefined") //IE route
             target.onselectstart=function(){return false}
          else if (typeof target.style.MozUserSelect!="undefined") //Firefox route
             target.style.MozUserSelect="none"
          else //All other route (ie: Opera)
             target.onmousedown=function(){return false}
          target.style.cursor = "default"
     }
</script>

disableSelection(document.body);  //禁止鼠标拖动复制以及Ctrl+A