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This article mainly introduces "JavaScript has several constants". In daily operation, I believe many people have doubts about several constant problems in JavaScript. The editor consulted all kinds of data and sorted out simple and easy-to-use operation methods. I hope it will be helpful for you to answer the doubts about "JavaScript has several constants"! Next, please follow the editor to study!

JavaScript has five kinds of constants, which are: 1, integer constant, which is actually positive; 2, real constant, which is actually decimal; 3, string constant, which is actually enclosed in single or double quotes; 4, Boolean constant; 5, custom constant, using "const constant name = constant value;" sentence definition.

The operating environment of this tutorial: windows7 system, javascript1.8.5 version, Dell G3 computer.

What is a constant?

Constants represent some fixed data

In real life, a person's gender can actually be regarded as a constant, born a boy all his life, a girl all his life.

Classification of constants in JavaScript

Integer constant

An integer constant is actually a positive number, and any integer written in JavaScript is an integer constant.

1 / 666 / 99

Real constant

A real constant is actually a decimal, and any decimal written in JavaScript is a real constant.

3.14 / 6.66

String constant

A string constant is actually something enclosed in single or double quotation marks, which we call a string constant.

'a'

'abc'

"1"

"BNTang"

Note: no matter how many characters are enclosed in single or double quotation marks, they are string constants in JavaScript

Boolean constant

Boolean constants are actually true or false, expressed by true and false in JavaScript

Boolean constants have only two values in JavaScript, true (true) or false (false)

Custom constant

New to ES6

Const constant name = constant value

Const NUM = 666 NUM / NUM = 888; / / if you try to modify the value of the constant, you will find that it is wrong. Once the constant is defined, you can no longer change the value of console.log (NUM). At this point, the study of "there are several constants of JavaScript" is over. I hope you can solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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