Java Script Is a Scripting Language, and It's Not a Programming Language

The first language feature that should be avoided is the in operator. In java script, unlike many other programming languages, once something makes it in, it can never be removed. The with keyword or with statement is one of the really few things in javascript that i can think of that's been effectively removed out of the language. And then there are better alternatives to what they expect developers to do exactly what they expect them to do.