用jquery做登陆

   < table  style ="border:solid 1px #EDEDED;height:112px;width:211px;left: 463px; top: 257px; text-align: center;" >
     < tr >
       < td >
         < table  id ="tblLogin"  border ="0"  cellpadding ="0"  style ="border-collapse: collapse"  width ="100%" >
           < tr >
             < td  style ="width: 62px; text-align: center; height: 37px; padding-top: 5px;" >
              用户名： </ td >
             < td >
               < asp:TextBox  ID ="tbUser"  CssClass ="tb20"  runat ="server"  Font-Size ="0.8em"  MaxLength ="20"
                Style ="font-size: 12px"  Width ="120px" ></ asp:TextBox >
               &nbsp;
             </ td >
           </ tr >
           < tr >
             < td  style ="width: 62px; text-align: center; padding-top: 5px;" >
              密 &nbsp;&nbsp;&nbsp; 码： </ td >
             < td >
               < asp:TextBox  ID ="tbPass"  CssClass ="tb20"  runat ="server"  Font-Size ="0.8em"  MaxLength ="20"
                Style ="font-size: 12px"  TextMode ="Password"  Width ="120px" ></ asp:TextBox >
               &nbsp;
             </ td >
           </ tr >
           < tr >
             < td  colspan ="2"  style ="text-align: center;padding:5px;" >
               < input  type ="button"  id ="btnLogin"  class ="btn5"  value =" 登 录 "  onclick ="return login();" /></ td >
           </ tr >
         </ table >
         < div  id ="msg"  style ="color:#f00;font-weight:bold;height:15px;" ></ div >
       </ td >
     </ tr >
   </ table >
   < script  type ="text/javascript"  language ="javascript" >
   <!--
    
    $( " #<%=tbUser.ClientID %> " ).focus();
            
     function  login()
    {
       var  u  =  $( " #<%=tbUser.ClientID %> " ).val();
       var  p  =  $( " #<%=tbPass.ClientID %> " ).val();
      $.ajax({
         //  定义是post传递
        type: " POST " ,
         //  要传值到的aciton
        url: " Login.aspx " ,
         //  跟上要传的参数名和值
        data: " t=login&u= " + u + " &p= " + p,
         // 当ajax发生错误的时候
        error: function  () {
          alert( " error " );
        }, 
         // 当ajax成功的时候
        success: function  (msg) {
           var  a  =  msg.substring( 0 ,  1 );
           var  b  =  msg.substring( 2 , msg.length);
           if  (a  ==   " 1 " ) {
            $( " #msg " ).html(b);
            $( " #tblLogin " ).css({ " display " : " none " });
            window.top.location.href  =   " default.aspx " ;
          }
           else {
            $( " #msg " ).html(b);
            $( " #btnLogin " ).removeAttr( " disabled " );
            $( " #<%=tbUser.ClientID %> " ).focus();
          }
        }
      });
    }
    
    document.onkeydown = function (event){
          e  =  event  ?  event :(window.event  ?  window.event :  null ); 
           if (e.keyCode == 13 ){ 
        $( " #msg " ).html( " 正在登录 …… " );
        $( " #btnLogin " ).focus(); 
        $( " #btnLogin " ).attr( " disabled " ,  true );
              login();
          }
      }
   // -->
   </ script >

 

后台代码返回字符串格式为string.Format("0,{0}", "用户名不能为空！");