var options = {
                //参数说明：
                //1.用此方式提交时，form不能为runat="server"；
                //2.必须在表单form中加method="post"，此参数中加的method:'post'不能提交含大量表单域的form；
                //3.必须在cs文件中用Request["名称"]获取表单域的值，否则RequestString获取字符串长度有限制.
                target: '#lblInfo',
                method: 'post',
                url: 'AnnouncementAdd.aspx?type=add&ColumnID=<%=nColumnID %>',
                beforeSubmit: function () {
                    // $('#btnModify').linkbutton({disabled:true});    // disable the button 
                },
                success: function (msg) {
                    if (msg == "1") {
                        $("#lblInfo").text("新增成功！(" + Title + ")");
                    }
                    else if (msg == "2") {
                        $("#lblInfo").text("不能重复提交信息！");
                    }
                    else
                        $("#lblInfo").text("新增有误，请检查！");
                    return false;
                },
                error: function () { $.messager.alert("操作提示", "请求异常！", "warning"); }
            };
 
            $('#form1').ajaxSubmit(options);
页面有个文本编辑器，表单提交时，字数少的时候能提交上去，字数一多就执行error，后台也进不去，谁能看看是啥问method: 'post', 换成type:'post' 试下

AnnouncementAdd.aspx

你的编辑器包含<>html字符吧。。提交到aspx页面会报错的如果没有给page指令添加 ValidateRequest="false"