Javascript 转换为数字不'；行不通

有人能给我解释一下为什么这个代码不能正常工作吗

var num = '10';

Number(num);
console.log(typeof(num));//string

parseInt(num);
console.log(typeof(num));//string

parseFloat(num, 10);
console.log(typeof(num));//string

console.log('-------------');

var num = '10';
var string = 'aklñjg';


num = Number(num);
string = Number(string);
console.log(typeof(num));//number
console.log(typeof(string));//number


num = parseInt(num);
string = parseInt(string);
console.log(typeof(num));//number
console.log(typeof(string));//number

console.log('++++++++++++++++');


    var num = '10';
var string = 'aklñjg';


num = Number(num);
string = Number(string);
console.log(typeof(num));//number
console.log(typeof(string));//number


num = parseInt(num, 10);
string = parseInt(string, 10);
console.log(typeof(num));//number
console.log(typeof(string));//number

或者all是字符串，或者all是数字

---

非常感谢您的帮助。

您说的工作不正常是什么意思？谢谢，我不懂javascript，也不把NaN理解为一个数字。“不是一个数字”就是一个数字，这似乎是一个矛盾修饰法！！！javascript的许多可爱特性之一，有时会让你陷入沉思！

var num = '10'; // num is a string

Number(num); // you've done nothing with the RESULT, num is unchanged
console.log(typeof(num));//string - because you haven't changed num

parseInt(num); // you've done nothing with the RESULT, num is unchanged
console.log(typeof(num));//string - because you haven't changed num

parseFloat(num, 10); // you've done nothing with the RESULT, num is unchanged
console.log(typeof(num));//string - because you haven't changed num

var num = '10'; // num is a string
var string = 'aklñjg';  string is a string


num = Number(num); // num is a Number
string = Number(string);// string is a Number (NaN (not a number) is a number!)
console.log(typeof(num));//number 
console.log(typeof(string));//number


num = parseInt(num); // num is a number
string = parseInt(string); // string is a number (NaN still a number)
console.log(typeof(num));//number
console.log(typeof(string));//number