登录成功之后跳转回原先载入的链接

1、需登录之后才能查看的页面，首先判断是否登录，未登录时去到登录页面，参数formUrl的值是登录前要去到的链接

if(!IsUserLogin()){
        string hostAndPort = HttpContext.Current.Request.Url.AbsoluteUri.ToLower();
        if (!string.IsNullOrEmpty(HttpContext.Current.Request.Url.Query))
            hostAndPort = hostAndPort.Replace(HttpContext.Current.Request.Url.Query.ToLower(), "");
        if (!string.IsNullOrEmpty(HttpContext.Current.Request.Url.LocalPath))
            hostAndPort = hostAndPort.Replace(HttpContext.Current.Request.Url.LocalPath.ToLower(), "");
        Response.Redirect("/zh_cn/login.html?fromUrl=" + Server.UrlEncode(hostAndPort + HttpContext.Current.Request.RawUrl));
        Response.End();
}

2、登录页面脚本

$(function() {
    $('.sub').click(function() {
        var str = '';
        var index = document.URL.indexOf("fromUrl=");
        if (index == -1) {
            var fromUrl = "";
        } else {
            var fromUrl = document.URL.slice(index + 8);
        }
        if ($('#username').val() == '') {
            str += '用户名不能为空
';
        }
        if ($('#password').val() == '') {
            str += '密码不能为空
';
        }
        if (str.length > 0) {
            alert(str);
            return false;
        } else {
            $.post('/tools/submit_ajax.ashx?action=user_login&site={site.build_path}&fromUrl=' + fromUrl, $('#form_login').serialize(), function(data) {
                if (data.status == 1) {
                    if (data.url != "") {
                        location.href = data.url;
                    } else {
                        location.href = "/zh_cn/index.html";
                    }
                } else {
                    alert(data.info);
                }
            }, 'json')
            return false;
        }
    })
})

 3、一般处理程序

string fromUrl = STRequest.GetQueryString("fromUrl");
context.Response.Write("{"status":1, "info":"会员登录成功！","url":"" + fromUrl + ""}");