JavaScript Hoisting case analysis

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

JavaScript Hoisting states that it will be promoted

Hoisting is the default behavior for JavaScript to move the declaration to the top.

JavaScript states that it will be promoted

In JavaScript, you can declare a variable after you use it.

In other words, you can use a variable before declaring it.

Example 1 has the same result as example 2:

Example 1

X = 5; / / assign 5 to x

Elem = document.getElementById ("demo"); / / find the element

Elm [XSS _ clean] = x; / / display x in the element

Var x; / / declare x

Example 2

Var x; / / declare x

X = 5; / / assign 5 to x

Elem = document.getElementById ("demo"); / / find the element

Elm [XSS _ clean] = x; / / display x in the element

To understand this, you must understand the term "hoisting".

Hoisting is the default behavior for JavaScript to promote all declarations to the top of the current scope (to the top of the current script or function).

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