js触发回车事件

<script type="text/javascript">
function document.onkeydown() {                 //网页内按下回车触发
    if(event.keyCode==13)
    {
        document.getElementById("Button").click();   
        return false;                               
     }
}
</script>

 

< script type = " text/javascript " >
document.onkeydown = ShowEnterKey;
  if    (event.keyCode == 13 )   
 {   
  event.keyCode = 0 ;
  event.returnValue    =     false ;
  alert( " hhaha " );
 } 
}
< / script>