C#中关于timer的简单问题！！

后台：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {    }
    static int AllTime = 20;
    static int time = AllTime;//剩余的答题时间
    protected void Timer1_Tick(object sender, EventArgs e)
    {
        int minute;//当前分
        int second;//秒
        if (time > 0)
        {
            time--;
            minute = time / 60;
            second = time % 60;
            Label1.Text = string.Format("{0:00}：{1:00}", minute, second);
            //GC.KeepAlive(time);
        }
        else
        {            System.Web.UI.ScriptManager.RegisterStartupScript(this, this.GetType(), "", " <script language='javascript'>window.open('', '_self');window.close();</script>", false);
        }
    }
    protected void Button1_Click(object sender, EventArgs e)
    {        this.Timer1.Enabled = true;
        Timer1_Tick(this, e);
    }
}
前台：
<%@ Page Language="C#" AutoEventWireup="true"  CodeFile="Default.aspx.cs" Inherits="_Default" %><!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></title>
</head>
<body>
    <form id="form1" runat="server">
    <div>

        <asp:ScriptManager ID="ScriptManager1" runat="server">
        </asp:ScriptManager>
        <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />
        <asp:UpdatePanel ID="UpdatePanel1" runat="server">
            <ContentTemplate>
                <asp:Timer ID="Timer1" runat="server" Interval="1000" ontick="Timer1_Tick"
                    Enabled="False">
                </asp:Timer>
                <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
            </ContentTemplate>
        </asp:UpdatePanel>

    </div>
    </form>
</body>
</html>我想请问下，为什么我第一次运行点击按钮后，timer会运行，然后我关闭网页，在次打开网页，在点击按钮，label显示的时间是上次我关闭页面的时间？？？？？？？为什么？？？

解决方案 »

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设置 "Cache-Control" "no-cache"
有时候Timer的Enble=false并不能将tick的次数归为0，结束后Dispose下试试
static int time = AllTime;//剩余的答题时间 time不要用static的，保存在ViewState里或者是 Page_Load 里 !IsPostback的时候清零一下
是JS错误！‘sys未定义’ 在webconfig 里添加httphandler解决方法：
<?xml version="1.0"?>

<configuration>
<appSettings/>
<connectionStrings/>
<system.web>
    <httpHandlers>      <remove verb="*" path="*.asmx"/>      <add verb="*" path="*.asmx" validate="false" type="Microsoft.Web.Script.Services.ScriptHandlerFactory, Microsoft.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>      <add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"/>      <add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" validate="false"/>    </httpHandlers>

<compilation debug="true">
<assemblies>
<add assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
        <add assembly="System.Web.Extensions, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
        <add assembly="System.Web.Extensions.Design, Version=1.0.61025.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
      </assemblies></compilation>


<authentication mode="Windows"/>

</system.web>
</configuration>
我知道了，不是缓存的问题！ protected void Button1_Click(object sender, EventArgs e)
  {

  this.Timer1.Enabled = true;
  time=20;
  Timer1_Tick(this, e);
  }