AJAX请求，弹出下载框

悬赏园豆：15 [已关闭问题]

AJAX请求服务器端，在ASP.NET MVC下，竟然弹出下载框~

客户端代码如下：

Code
$("#commentForm").submit(function() {
            if (!$("#commentForm").valid()) {
                return false;
            }else{
            event.preventDefault(); 
            var groundID =<%=ViewData["GroundID"] %>;
            var fengJin = $("#fengJin").val();
            var jiaoTong = $("#jiaoTong").val();
            var meiShi = $("#meiShi").val();
            var zhuSu = $("#zhuSu").val();
            var yuLe = $("#yuLe").val();
            var content = $("#leavewordContent").val();
            var commentContent = $("#commentContent").val();
            $("#submitLoading").show();
            $.ajax({
                type: "POST",
                url: "/ground/Json_CommentPost",
                data: "groundID="+groundID+"&fengJin="+fengJin+"&jiaoTong="+jiaoTong+"&meiShi"+meiShi+"&zhuSu="+zhuSu+"&yuLe"+yuLe+"&commentContent="+commentContent,
                dataType:"json",
                success: function(data) {
                    if(data.isSuccess)
                    {
                        $("#submitLoading").hide();
                        alert("感谢您的评论，我们会尽快审核，谢谢！");
                        switchingTab($("#liComment"));
                        
                    }else
                    {
                        alert(data.messageContent);
                    }     
                }
            }); 
            }