JS data type Getting started with typeof operator

Standard data type partitioning:

Basic type:

Number (numeric), string (string), Undefined, Boolean (Boolean), null (NULL object)

The biggest difference between an empty object and a non-empty object is that you cannot perform property operations

Object type (composite type):

Object (Objects)

There is no function in the object type and the function does not belong to the data;

typeof Operator:

is the data type used to detect variables, for values or variables. typeof The operator returns the string as follows. The code is as follows

var nub = ten; Console.log (typeof nub); Number number    /* numbers from negative infinity to positive infinity, and Nan (not a digit) */
var str = "Asdsadsad"; String string Console.log (typeof str);/*    any string of characters enclosed in quotation marks are strings */
var is = true;  Boolean Boolean value Console.log (typeof is);/*    true and false*/
var arr = []; Object Object Console.log (typeof arr); Console.log (null = = arr);//Note empty array is not equal to null object var obj = null; Object Console.log (typeof obj); var el = document; Object Object Console.log (typeof el);/*    objects: array, NULL, Element object, Object*/var u;//undefined undefined Console.log (typeof u); var fn = function () {//function    alert (1);} Console.log (typeof fn), function fn2 () {//function     alert (2);} Console.log (typeof fn2);

The data types in typeof are divided into:

• Number
• String
• Undefined
• Boolean
• Object
• function

JS data type Getting started with typeof operator