Yes sure, no prob! Here it is:
http://www.skybyte.net/articles/prototype.js/
You can find it by keywords: "$a is not defined prototype.js"
You can't find it anymore by: "$a is not defined prototype"
As usual, I messed up with the description for this article, I've changed it 4 times already
LOL, you know me, I like to experiment and I learn! So, two letters "js" makes a difference between 2.200.000 and 30.000! LOL, it was 3rd between 3ml... LOL