Javascript Math: get the signature of a number

gistfile1.txt

/**
 * return the signature of a number.
 *
 * @param {number} val		the input value
 * @return {number} 		1 if positive, -1 if negative, else 0
 */
Math.sign = function( val ) {
	return val > 0 ? 1 : val < 0 ? -1 : 0;
};