javascript help with variables

With some help, I wrote this javascript.

http://pastebin.com/uSSZp0j6

I don't understand how to add more than one variable to a variable, I need for there to be several "keycodes," not just one. Other than that, the script works fine.

>>12
Arrays are fine (although new Array is pointless). The in operator is dangerous as it returns true when a property is found anywhere in an object's prototype chain, which is not what you want in this case. It's also no faster than a simple array iteration. [1]

[1] http://jsperf.com/in-vs-array-iteration