If you compiled sl2 to asm.js and integrated in some way with <textarea> tags in-browser, it would make editing content in most CMSes far more convenient. Some people are already using emscripten to do this with the qt-based Kate editor. Here are a few demos:
http://vps2.etotheipiplusone.com:30176/ ... /kate.html
http://vps2.etotheipiplusone.com:30176/ ... wiki/Demos
As integration between asm.js and <textarea> goes... In the case there aren't any other options, maybe the integration code could periodically update the <textarea> sl2 augments with the contents of a designated file on the asm.js virtual filesystem?
I'm about 100% sure I could convince my coworkers to buy a license if we could run sl2 in a browser.