How to box a formula in MathJax?

How do I draw a box around a formula in MathJax?

I've seen \boxed{} 开发者_JS百科recommended for LaTeX in general, but MathJax doesn't support that operation. Is there an alternative that does the trick?

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\boxed is in the AMSmath extension, so if you put "TeX/AMSmath.js" in the extensions array of your configuration, you will be able to use the \boxed{} macro. Alternatively, try \fbox{}.