Math.sign
//The Math.sign() function returns either a positive or negative +/- 1,
//indicating the sign of a number passed into the argument. If the number passed into
//Math.sign() is 0, it will return a +/- 0. Note that if the number is positive,
//an explicit (+) will not be returned.
Math.sign(3); // 1
Math.sign(-3); // -1
Math.sign('-3'); // -1
Math.sign(0); // 0
Math.sign(-0); // -0
Math.sign(NaN); // NaN
Math.sign('foo'); // NaN
Math.sign(); // NaN
Scary Snake