网页中屏蔽右键,不允许选择文本.兼容IE,Firefox

<style> 
  body   { 
    -moz-user-select : none; 
  } 
</style>  
<script>
document.oncontextmenu=function(e){return   false;}
window.onload = function(){
 document.body.onmouseup = function (){document.selection.empty();};
 document.body.oncontextmenu = function () {return false;};
 document.body.onselectstart = function () {return false;};
 document.body.onselect = function () {document.selection.empty()};
}
</script>