After banging my head for days on a “A potentially dangerous Request.Form value was detected" issue when post (ajax-ing) a form in ASP.NET MVC 2 on .NET 4.0 framework using jQuery and CKEditor, I found that when you use the following: Code Snippet $.ajax({ url: '/TheArea/Root/Add', type: 'POST', data: $("#form0Add").serialize(), dataType: 'json', //contentType: 'application/json; charset=utf-8', beforeSend: function () { pageNotify("NotifyMsgConten... "MsgDefaultDiv", '<img src="/Content/images/conten...