We just added three new theme variable transformations:

Plaintext. Prefix any theme variable with “Plaintext” to output the string with HTML-tags stripped and appropriate characters converted to HTML-entities (so they’re safe to include in HTML attributes, etc.).
<a href="{URL}" title="{PlaintextName}">{Name}</a>

Javascript. Prefix any theme variable with “JS” to output a Javascript string (wrapped in quotes).
var description = {JSDescription};

Javascript Plaintext. Prefix any theme variable with “JSPlaintext” to output a Javascript string (wrapped in quotes) with HTML-tags stripped and appropriate characters converted to HTML-entities.
var description = {JSPlaintextDescription};