Moodle 2.5 and 2.4 with JSXGraph and MathJax installed.

When I use just MathJax equations on page, all cyrillic characters seems to be ok:

But when I add JSXGraph plot to a page, it breaks non-latin charactes this way:

Page source:

<p>Tangent:</p> <p>$$ \tan\left(x\right)=\frac{\sin\left(x\right)}{\cos\left(x\right)}$$</p> <p>ÐšÐ¾Ñ‚Ð°Ð½Ð³ÐµÐ½Ñ:</p> <p>$$ \cot\left(x\right)=\frac{\cos\left(x\right)}{\sin\left(x\right)}$$</p> <p>Ð¡ÐµÐºÐ°Ð½Ñ:</p> <p>$$ \sec\left(x\right)=\frac{1}{\sin\left(x\right)}$$</p>

Any suggestions?