Find Odd Number

OddNumber.js

The "trick" is to binary AND a value with 1.
Any odd number must have the first bit set to 1.

So

var foo = 7;

if( foo & 1 ) { // true }

Using a bitwise AND has a better performance in almost all platforms / browsers.

for(var loop = 0; loop < 10; loop++) {
    if( loop & 1 ) {
        console.log('I am ', loop, ' and I am odd!');
    }
}