isNaN()

判断一个值是否为NaN数值。

示例

function milliseconds(x) {
  if (isNaN(x)) {
    return "Not a Number!";
  }
  return x * 1000;
}

console.log(milliseconds("100F"));
// expected output: "Not a Number!"

console.log(milliseconds("0.0314E+2"));
// expected output: 3140