JS Number Type

Number: Positive, negative, 0, decimal, NaN

Nan:not A number is not a valid digit but he is a numeric data type of

var num = 12;

12==12 comparison

var a= 12 Assignment;

IsNaN (); detects whether a value is a valid number if the proposition is true, is a valid number that returns FALSE, is not a valid number to return;

If the detected value is not of type number, the browser will default to convert it to type # and then determine if it is a valid digit

Console.log (IsNaN ("123")) returns the result is False

First convert "123" to Number = Number = number ("123")

Number () forces other data types to be converted to type #, which requires numbers in a string to be converted if they are strings

Number ("==>12") Number ("12px") ==>nan

Non-mandatory data type conversion parseint/parsefloat

Console.log (parseint ("12px"));

From left to right, a character search, the number is converted to a valid number, midway if you encounter a non-valid number, will not continue to find

Parsefloat () ibid.

JS Number Type