JavaScript scope oddities

gistfile1.js

/*
 * This is just a short demo of some of the scoping
 * oddities in JS that you should watch out for.
 */

var x = 1;
console.log(x);

function foo() {
    console.log(x);
    var x = 2;
    console.log(x);
}

foo()
console.log(x);

// Console output:
//> 1
//> undefined
//> 2
//> 1

/*
 * The reason for this is that variables
 * are created (and scoped) at compile
 * time, but are not assigned until the
 * particular line is executed.
 */