Edit the formulas below (the display updates dynamically). If you know (La)TeX formula syntax, you can try some of that as well (LaTeX formulas work best when enclosed in $-signs). The "amath" token switches on the new auto-math-recognize mode.
Note that this is dynamic XHTML running locally on your machine!
Right-click on an output formula to copy or view the MathML code.
This demo page shows that ASCIIMathML.js can be used easily to dynamically preview mathematical formulas (client-side). E.g. here is a (beta) webpage that can be used to write and read mathematical emails and discussion group articles. Since most email communication is still done with ASCII text (or at least not yet with XHTML), this is a reasonable (and inexpensive) solution for communicating with students in online math courses.