Javascript Number Object

Number ("");   // 0 Number ("DF");  // if it cannot be converted to a number, it returns Nan

Number method:

Number.isNaN()  0/0 → NaN   该方法不会强制将参数转换成数字，只有在参数是真正的数字类型，且值为 NaN的时候才会返回 true

Determines whether the passed value is NaN.

Number.isFinite()

Determines whether the value type passed and itself is a finite number.

Number.isInteger()

Determines whether the value type passed is "number" and is an integer.

Number.isSafeInteger()

Determine whether the passed value is a safe integer (number between -(253 - 1) and 253 - 1 ).

Number.toInteger()

computes the passed value and converts it to an integer (or infinity).

Number.parseFloat() 　　parseFloat()方法将参数中指定的字符串解析成为一个浮点数字并返回

The same as the global object parseFloat() .

Number.parseInt() 　　parseInt() 函数将给定的字符串以指定基数（radix/base）解析成为整数

The same as the global object parseInt() .

parseint (stringradix);

Javascript Number Object