CheckBoxList垂直方向对齐问题

 

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="20110829.aspx.cs" Inherits="_20110829" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
    <title>CheckBoxList垂直方向对齐问题</title>
   <script type="text/javascript" src="jquery.js" ></script>
</head>
<body>
    <form id="form1" runat="server">
    <div>
       <asp:CheckBoxList ID="CbRoles" runat="server" RepeatColumns="3" Width="100">
        </asp:CheckBoxList>
         <script type="text/javascript" >       
           //$("tr:first").attr("valign","top");失败
           //$("#CbRoles:tr:first").css("vertical-align", "top"); 失败
           //$("tr:first").css("vertical-align", "top");失败
           $("#CbRoles").find("tr").css("vertical-align", "top"); //OK
         </script>
    </div>
    </form>   
</body>
</html>