Don't use future reserved words as identifiers in JavaScript

Just a quick note: I found recently that some browsers don’t complain when I use future reserved words as identifiers in JavaScript. Specifically, I used char as a variable name, and no Windows browser had a problem with it – but when I tested on Mac, both Safari and Firefox complained. Apparently there are differences in JavaScript implementation between the Windows and Mac versions of Firefox 1.5!

Nitty-gritty details: the ECMA-262 spec defines reserved words and future reserved words in section 7.5.1. Many OO-ish keywords like implements are reserved for the future, as well as specific data types like int and … you guessed it, char.

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I'm Baron Schwartz, the founder and CEO of VividCortex. I am the author of High Performance MySQL and lots of open-source software for performance analysis, monitoring, and system administration. I contribute to various database communities such as Oracle, PostgreSQL, Redis and MongoDB. More about me.