a browser

CouchDB

console,alert, ...

Node.js

Rhino

Stop on first error

assignment expressions

bitwise operators

Google Closure

continue

debugger statements

== and !=

eval

unfilteredfor in

uncapitalized constructors

dangling _ in identifiers

++ and --

. and [^...] in /RegExp/

unused parameters

missing 'use strict' pragma

stupidity

inefficient subscripting

TODO comments

many var statements per function

messy white space