I have MathJax formulae not beautiful in Chrome browser. I remember I installed something for MathML support but can't find any traces now.
Formulae in Chrome
Formulae in Firefox
UPDATE
There are 3 errors in Console:
Port error: Could not establish connection. Receiving end does not exist.
located in miscelaneous_bindings script in function
// Called by native code when a channel has been closed.
chromeHidden.Port.dispatchOnDisconnect = function(
From the screenshots, it looks as if MathJax is running successfully but is producing native MathML output (and you're using Chrome 23 or older).
Even though MathJax uses HTML+CSS output by default, this can be changed and will be stored as a preference in a cookie.
Try right-clicking on one of the formulas to trigger the MathJax context menu where you change the rendering mechanism back to the default HTML-CSS (or the SVG-output).
Deleting the MathJax cookie should help, too.
