You may get this error message A potentially dangerous Request.Form value was detected from the client when you try to submit a html content on your site. By default validation input is turned on, this is used to reduce the possibility hack or attack on your site. When you decide to disable this make sure it is only apply to the specific page of your site.
How to solve this issue in MVC?
To solve this issue is pretty simple, in your controller action view, you just need to set the ValidationInput to false. See below example.
[HttpPost] [ValidateInput(false)] public ActionResult SubmitContent(string value) { }