4.4 Common Markdown Extensions ↑

4.4.7 Highlight

As an extension to the original Markdown spec from John Gruber, highlighting is supported, in conformance with the Markdown Guide to Extended Syntax.

In order to produce a span of highlighted text, place a pair of equal signs (==) before and after the content to be highlighted.

So the following line…

A is true. ==B is no longer true.== C is also true. 

…would produce the following effect:

A is true. B is no longer true. C is also true.