function check(object)
{ 
 var s =document.getElementById(object.id).value; 
    var pattern =/^[a-zA-Z0-9_/-]{1,}@[a-zA-Z0-9_/-]{1,}/.[a-zA-Z0-9_/-.]{1,}$/;
    if(s!="")
    {alert("1");
       if(!pattern.exec(s))
       {alert("2");
          alert('请输入正确的邮箱地址');
          object.value="";
          object.focus();
       }
    }
}