15.8.2.17 Math.sqrt(x)

number Math.sqrt(x)

Return the square root of x.

Math.sqrt = function(x){
x = ToNumber(x);
if (isNaN(x)) return NaN;
if (x < 0) return NaN;
if (x === +0) return +0;
if (x === -0) return -0;
if (x == +Infinity) return +Infinity;
return Math.sqrt(x);
// return Math.pow(x, 0.5); // 1/2
}