For algorithmic discussion, try the Chess Programming Wiki.
Techniques suited to serious chess engines are not necessarily right for web based games. Real chess engines run orders of magnitude faster, using multi-megabyte opening books and spending minutes or hours on each turn. A real chess engine will search deeper than 12 ply, while javascript won t get far past 6 ply in reasonable web time. Therefore something like a piece-square oracle, which has diminishing and possibly negative returns as search deepens and is consequently well out of fashion in chess programming circles, is arguably well suited to a javascript engine. If you do what people were doing in the 80s, you will end up with a snappy and manageable engine that will beat most visitors.
And of course you don t really want to look up what other people are doing. Just make sure you have some variation of a alpha-beta search, then tweak your evaluation function and everything else as you see fit.
In 2002 and 2012 I wrote then rewrote p4wn, a small public domain javascript engine. It uses alpha-beta and a piece-square oracle. It is probably weaker than Garbochess-JS, but then Garbochess has an opening book that is bigger that the entire p4wn engine.