取ID：
<%@ Page Title="" Language="C#" MasterPageFile="~/Master/ERP.Master" AutoEventWireup="true" CodeBehind="index.aspx.cs" Inherits="AspxERP.Web.Master.index" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
<script src="../Scripts/jquery-1.4.4.min.js" type="text/javascript"></script>
<script type="text/javascript">
$(function () {
$("#<%=TextBox1.ClientID%>").blur(function () { alert("x"); });
});
</script>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<p>
欢迎使用！</p>
<asp:TextBox ID="TextBox1" runat="server" CssClass="Aactiv"></asp:TextBox>
</asp:Content>
取Class:
<%@ Page Title="" Language="C#" MasterPageFile="~/Master/ERP.Master" AutoEventWireup="true" CodeBehind="index.aspx.cs" Inherits="AspxERP.Web.Master.index" %>
<asp:Content ID="Content1" ContentPlaceHolderID="head" runat="server">
<script src="../Scripts/jquery-1.4.4.min.js" type="text/javascript"></script>
<script type="text/javascript">
$(function () {
$(".<%=TextBox1.CssClass%>").blur(function () { alert("x"); });
});
</script>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" runat="server">
<p>
欢迎使用！</p>
<asp:TextBox ID="TextBox1" runat="server" CssClass="Aactiv"></asp:TextBox>
</asp:Content>
比较简单 我记录下 以后忘记了可以来查下