js 回车提交与回车登录代码

//回车的键值为13 
function document.onkeydown(){ 
   if (event.keyCode == 13) { 
       //js 监听对应的id 
       document.getElementById("login_1").click(); 
       return false ; 
      } 
} 

function loginSystem() { 
  if(!(submitForm()) ) { 
      return false; 
  } 
    //表单提交 
     document.dataForm.submit(); 
} 

<div id="btn">
<a href="javascript:void(0);" id="login_1" onclick="loginSystem()">登录</a>
<a href="javascript:void(0);" onclick="clearSystem()">清空</a></div> 
 

<form name="dataForm" method="post" action="loginAction.do?method=checkUser"> 

#btn{margin-left:30px; margin-top:40px;height:25px; margin-right:28px; text-align:center;} 
#btn a{display:block; line-height:25px; background: url(bt_bg.gif); border: solid 1px #b6b6b6; width:65px; float:left; margin-left:15px; text-decoration:none; color:#000;} 
 

onpropertychange="seach()"