【图】用javascript实现（页面正在加载的效果）

代码文件：

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Threading;
namespace AjaxTest
{
    /**//// summary
    /// WebForm2 的摘要说明。
    /// /summary
    public class WebForm2 : System.Web.UI.Page
    {
        protected System.Web.UI.WebControls.Button Button1;
        protected System.Web.UI.WebControls.Label Label1;

        private void Page_Load(object sender, System.EventArgs e)
        {
            Response.Write("div id='mydiv' ");
            Response.Write("_");
            Response.Write("/div");
            Response.Write("scriptmydiv.innerText = '';/script");
            Response.Write("script language=javascript;");
            Response.Write("var dots = 0;var dotmax = 10;function ShowWait()");
            Response.Write("{var output; output = '正在装载页面';dots++;if(dots=dotmax)dots=1;");
            Response.Write("for(var x = 0;x dots;x++){output += '·';}mydiv.innerText = output;}");
            Response.Write("function StartShowWait(){mydiv.style.visibility = 'visible'; ");
            Response.Write("window.setInterval('ShowWait()',1000);}");
            Response.Write("function HideWait(){mydiv.style.visibility = 'hidden';");
            Response.Write("window.clearInterval();}");
            Response.Write("StartShowWait();/script");
            Response.Flush();//这一句是最关键的
        }

        private void Button1_Click(object sender, System.EventArgs e)
        {
            //当点击按钮时，假设请求需要较长时间(这里设置为10秒)
            System.Threading.Thread.Sleep(10000);
            this.Label1.Text = "终于加载完成啦";
        }

        Web 窗体设计器生成的代码#region Web 窗体设计器生成的代码
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
            //
            InitializeComponent();
            base.OnInit(e);
        }

        /**//// summary
        /// 设计器支持所需的方法 - 不要使用代码编辑器修改
        /// 此方法的内容。
        /// /summary
        private void InitializeComponent()
        {
            this.Button1.Click += new System.EventHandler(this.Button1_Click);
            this.Load += new System.EventHandler(this.Page_Load);

}
#endregion

}
}

页面文件：
%@ Page language="c#" Codebehind="WebForm2.aspx.cs" AutoEventWireup="false" Inherits="AjaxTest.WebForm2" %
!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
HTML
    HEAD
        titleWebForm2/title
        meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1"
        meta name="CODE_LANGUAGE" Content="C#"
        meta name="vs_defaultClientScript" content="JavaScript"
        meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5"
        script
         HideWait();
        /script
    /HEAD
    body MS_POSITIONING="GridLayout"
        form id="Form1" method="post" runat="server"
            FONT face="宋体"
                asp:Button id="Button1" style="Z-INDEX: 101; LEFT: 480px; POSITION: absolute; TOP: 200px" runat="server"
                    Text="Button"/asp:Button
                asp:Label id="Label1" style="Z-INDEX: 102; LEFT: 632px; POSITION: absolute; TOP: 240px" runat="server"Label/asp:Label/FONT
        /form
    /body
/HTML