difference between undefined and null

Before the cloud-dwelling community sent a similar articleJavaScript null and undefined difference analysisJavaScript undefined,null type and nan value differenceLet's talk about undefined:The variables in JavaScript are weakly typed (I don't need

1. Type analysis:JS data types have undefined,boolean,number,string,object, such as 5, the first 4 are the original type, the 5th is the reference type.CodeCode highlighting produced by Actipro Codehighlighter (freeware)

Null: indicates no value;Undefined: Represents an undeclared variable, or a variable that has been declared but not assigned a value, or an object property that does not exist. The = = operator considers the two equal. If you want to differentiate

Most computer languages have and have only one value that represents "none", for example, the Null,java language of the C language, the Null,python language of the None,ruby language of nil.Oddly enough, the JavaScript language actually has two

Most computer languages have and have only one value that represents "none", for example, the Null,java language of the C language, the Null,python language of the None,ruby language of nil.Oddly enough, the JavaScript language actually has two

A bad time to answer, especially undefined, because this involves the realization of the principle of undefined. So, after thinking carefully, write down this article, please heroes to shoot bricks. Total known: null = = undefined However: null!==

Here is a collection of JS in the null and undefined two hints of the difference between analysis, for each beginner should have no small use OH. Generally known:Null = = undefinedBut:Null!== undefinedSo what's the difference between the

In JavaScript development, people ask: what is the difference between null and undefined? A bad time to answer, especially undefined, because it involves the implementation of undefined principle.General known: null = = undefinedHowever: null!==

In fact, I've listed all the "null" and "false" values in JavaScript, except that the Boolean value itself is true and false, "null values" for other data types are mainly undefined and defined. The types of these null values are: The

It is hard to answer at a time, especially undefined, because it involves the implementation principle of undefined. So, after thinking about it, write down this article. Please take a look.Total offices: null = undefinedBut: null! = UndefinedSo