JavaScript屏蔽鼠标右键

<HTML><HEAD>
<script language="javascript">
<!--
document.onkeydown = function()
 {
 if(event.keyCode==116) {
  event.keyCode=0;
  event.returnValue = false;
 }
}
document.oncontextmenu = function() {event.returnValue = false;}
-->
</script>
<TITLE>Background</TITLE>
<style type="text/css">
<!--
.STYLE1 {font-size: 13px}
-->
</style>
</HEAD>
<BODY text=#333333 link=#333333 vLink=#333333 aLink=#333333
leftMargin=2 topMargin=0 marginwidth="0" marginheight="0" oncontextmenu="window.event.returnValue=false" ondragstart='return false' onselectstart ='return false' onselect='document.selection.empty()' oncopy='document.selection.empty()' onbeforecopy='return false' onmouseup='document.selection.empty()'>
<DIV align=center>
  <TABLE width=100% height=100% border=0 align="left" cellPadding=0 cellSpacing=0>
    <TBODY>
      <TR vAlign=top>
        <TD align="center" valign="middle" bgcolor="#FFFFFF" ><img src="img/amnzyy.JPG" width="264" height="90">
        <div align="center"></div></TD>
      </TR>
      <TR vAlign=top>
        <TD height="196" ><div align="center" style="cursor:default">
          内容
        </div>
          <div align="center"></div></TD>
      </TR>
    </TBODY>
  </TABLE>
  <BR>
</DIV></BODY></HTML>