element is used to define subscript—text which appears half a character’s
height below the baseline of the line it’s on, and is most often used in
mathematical or chemical formulae.
The example HTML, where the number 2 is defined as subscript, would render on screen as shown in Figure 1.
Here’s an example of the
sub element used for chemical formulas:
<p>That's not just water. That's not just H<sub>2</sub>O. That's H<sub>2</sub>-woah!</p>
Use This For …
This element can be applied to any text content, but is likely to be limited to scientific or niche content.
sub element enjoys good browser