Formatting fraction fir display

I’m formatting fraction with MathJax and are having problem displaying it properly.

$disp = '<h1>$${{10 \over 9 }} of 99 $$</h1><br>';
echo $disp;

For some reason, i cannot get a space before and after the word ‘of’. Any pointers is greatly appreciated. Thanx in advance.

>Solution :

Usually, \ keep the space between letters.

$disp = '<h1>$${{10 \over 9 }}\ of\ 99 $$</h1><br>';

Reference – Spacing in math mode