I recently updated jquery 1.8.3 to 1.9 and started receiving, "Object doesn't support property or method" errors. I found out, not surprisingly, there are numerous breaking changes. Reference --> http://jquery.com/upgrade-guide/1.9 ; many functions have been removed: live, toggle, etc. So naturally, the unobtrusive js files that come as part of the MVC 4 project template can not function. Here's the solution for this...
Step one:
Via NuGet, pull in the jquery-migrate file
Step two:
Inside your BundleConfig.cs file modify to the following:
bundles.Add(new ScriptBundle("~/bundles/jquery").Include(
...
I recently started a new project and thought I'd give MVC3 a whirl since it requires only a pure web experience (as opposed to WPF and MVVM). I came across a great post by Bob Cravens in which he does a great job demonstrating AJAX calls to ASP.NET MVC action methods using JQuery.