跳转到登陆页的时候验证码页面不刷新是怎么回事？

原先验证码是这么写的：

<div class="lib">
            <span class="lib_l">验证码：</span><span class="lib_r"><asp:TextBox ID="verifyCode_txt"
                runat="server" Width="90px" CssClass="r_text r_text3" runat="server" MaxLength="4"></asp:TextBox><a
                    href="#"><img id="imgVerify" alt="看不清？点击更换" onclick="this.src=this.src+'?'" src="VerifyCode.aspx?"
                        style="vertical-align: bottom;  80px; height: 20px; border: 1px solid #ccc;" /></a></span></div>

之后点击“重新登录”，
Response.Write("<script>window.parent.location.href='LoginNew2.aspx'</script>");

但之后我断点到VerifyCode.aspx.cs是没有访问到的，请问下这是怎么回事？？

论坛大牛给的解决方法:

一般都是IE缓存引起的

方案一:对页面进行不缓存处理
    protected void Page_Load(object sender, EventArgs e)
    {
        Response.Expires = 0;
        Response.CacheControl = "no-cache";
    }

方案二:<img标签用js输出
              <script type="text/javascript" language="JavaScript">
                   var numkey = Math.random();
                   numkey = Math.round(numkey*10000);
                   document.write("<img src="VerifyCode.aspx?k="+ numkey +"" onClick="this.src+=Math.random()" alt="图片看不清？点击重新得到验证码" style="cursor:pointer;" />");
                </script>

最有我用了第二种方法实现了，第一种方法依旧是失败的！！有待解决

<div class="lib">
            <span class="lib_l">验证码：</span><span class="lib_r"><asp:TextBox ID="verifyCode_txt"
                runat="server" Width="90px" CssClass="r_text r_text3" runat="server" MaxLength="4"></asp:TextBox><a
                    href="#">

                    <script type="text/javascript" language="JavaScript">
                    var numkey = Math.random();
                    numkey = Math.round(numkey*10000);
                    document.write("<img src="VerifyCode.aspx?k="+ numkey +"" onClick="this.src+=Math.random()" alt="图片看不清？点击重新得到验证码" style="vertical-align: bottom;  80px; height: 20px; border: 1px solid #ccc;cursor:pointer;" />");
                    </script>

                </a></span>
        </div>