Can't get JQuery working with VS 2012, framework 4.5

I have used JQuery a few times in the past on older versions of Visual Studio. Never had a problem.  But now I'm using VS 2012 and framework 4.5 and I cannot get any JQuery to work.  I can't get AJAX working either.  For example, I want to use a simple JQuery datepicker.  But nothing happens when I run my web page.  Is there some trick to get JQuery and AJAX to work with framework 4.5?
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