jquery判断邮箱格式问题

var search_str = /^[\w\-\.]+@[\w\-\.]+(\.\w+)+$/;
 var email_val = $("#Email").val();
 if(!search_str.test(email_val)){       
     alert("please input right email !");
     $(‘#Email‘).focus();
     return false;
 }

ar mail = $(‘#mail‘).val();
 if (mail != ‘‘) {//判断
    var reg = /^([a-zA-Z0-9_-])+@([a-zA-Z0-9_-])+((\.[a-zA-Z0-9_-]{2,3}){1,2})$/;
    if (!reg.test(mail)) {
        alert(‘邮箱格式不正确，请重新填写!‘);
       return false;
  }
}

<script src="/js/jquery-1.4.2.js" type="text/javascript"></script>
<script language="javascript">$(document).ready(function() {
  $(‘.error‘).hide();
  $(‘.submit‘).click(function(event){
   var email=$(‘.email‘).val();
   if(valid_email(email)) {
    $(‘.error‘).hide();
   } else {
    $(‘.error‘).show();
    event.preventDefault();
   }
  });
 });