Hate to nitpick, but blatant linkbait headline. It's not 80 lines of JavaScript. It's 80 lines of javascript + thousands more lines of JavaScript in the form of libraries.
Point taken. Some of the libraries are like the air we breath (e.g., jQuery) - I even forgot to mention it on the link page.
My point was with 80 lines of "purpose built" code - you can create a functioning wiki. But we do stand on the shoulders of giants - I hope I gave proper attribution.