15.8.2.10 Math.log(x)

number Math.log(x)

Return the natural logarithm of x.

Math.log = function(x){
x = ToNumber(x);
if (isNaN(x)) return NaN;
if (x < 0) return NaN;
if (x === +0) return -Infinity;
if (x === -0) return -Infinity;
if (x === 1) return 0;
if (x === +Infinity) return +Infinity;
return Math.log(x);
}