ASP.Net中利用AJAX、JS点击验证码自动更新功能

ASP.Net中利用AJAX、JS点击验证码自动更新功能

aspx:
<asp:image ID="Image1" runat="server" ImageUrl="gif.aspx" >
可以改为HTML控件：
<img id="Image1" onclick="changeVCode();" src="gif.aspx" style="cursor:hand;" alt="看不清楚，换个图片" />
CS:
Image1.Attributes.Add("alt","看不清楚，换个图片");
Image1.Attributes.Add("style", "cursor:hand;");
Image1.Attributes.Add("onclick", "changeVCode();");

JS：
function changeVCode()
{
    var cbo = new CallBackObject();　//CallBackObject为自己写的AJAX对象
    var gifUrl = "gif.aspx";　//生成验证码图片页面
    var imgid = document.getElementById("<%= this.Image1.ClientID %>");
    imgid.src = "/images/loading_16.gif";　//载入时显示的Loading图片
    document.getElementById("cCode").value="";　//清空录入框
    cbo.OnComplete = onChangeComplete;
    cbo.onError = cbo_Error;
    cbo.DoCallBack(gifUrl);
}
function onChangeComplete()
{
     var imgid = document.getElementById("<%= this.Image1.ClientID %>");
     imgid.src = "gif.aspx";
}