Form submitted twice after updating from ASP MVC 3 Preview to Beta

The duplicated jquery.unobtrusive-ajax.min.js can also happened if your controller returns a View() instead of PartialView().

I had the same problem using a AJAX.BeginForm call that is loaded dynamically using $.load() I solved it by removing the extra include of jquery.unobtrusive-ajax.min.js on the loaded form. That's the key!

I had the same problem, and i found the solution: I included the "jquery.unobtrusive-ajax.min.js"-Script twice :-)

Look at the generated HTML. In ASP.NET MVC 3 Beta there's new support for unobtrusive jquery based ajax and all the Ajax helpers use jquery now. Maybe there's something left with MS Ajax which causes the double call. Make sure you remove all the inclusions of MSAjax scripts from the page. Also why using Ajax.BeginForm when you could simply use Html.BeginForm with unobtrusive jquery?