This week we're looking at JavaScript, a very important language, since it is the only language that runs natively in client browsers. It can also run on the server side, but as the de-facto client language it is hugely important. Designed in 10 days in the 1990's by Brendan Eich since "if I didn't design it in less than 10 days, something much worse than JavaScript would have happened", JavaScript is a somewhat querky language that combines various elements from different existing languages, and has both great power and some dangerous pitfalls.