One can display mathematical formulas in plain HTML 4.0 on both Mac OS and MS Windows. You can read more about that here. Unfortunately, there is not any tag which can place the characters on top of each other. To achieve it we have to use few lines of CSS and HTML code.
Below the solution:
CSS:
span.subsup {
position: relative;
}
span.subsup sub {
position: absolute;
left: 0em;
bottom: -1.4em;
}
HTML:
CO < span class="subsup">< sup>2-< /sup>< sub>3< /sub>
Interesting thing is that you can create a fraction simply by making Superscript underline. Just like: < sup>< u>2-< /u>< /sup>.
