Render Mathjax in HTML tags

Mathjax Environment in HTML

I would like to render Mathjax within an HTML environment as illustrated in this post:

Unfortunately, as pointed out in the post, it does not render in the Editing Mode. Does anyone know a solution to make it so?

Example below:

a sample: Z_{c}

which, when rendered in Reading Mode renders Mathjax and surrounds the text by a big red box. Code below:

<div align="center"; style="border-width:3px; border-style:solid; border-color:#FF0000; padding: 1em;">a sample: <span class="math display">Z_{c}</span></div>