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This article mainly explains "what is the difference between null and undefined in javascript". The content in the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "what is the difference between null and undefined in javascript".

Difference

1. Null means there is a value, but it is empty.

Undefined semantically means that no one has ever set this value at all, so there is no definition.

2. We should note that null is actually a keyword, but undefined is not.

Example

In the field of local functions, you can still change the value of Undefined.

Function foo () {var undefined = 1; console.log (undefined);}

Null is a keyword, so it doesn't have this kind of problem. If we assign a value to Null, it will get it wrong.

Function foo () {var null = 0; console.log (null);} Thank you for your reading. The above is the content of "what is the difference between null and undefined in javascript?" after the study of this article, I believe you have a deeper understanding of the difference between null and undefined in javascript. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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