How to define the scope and global scope of functions in HTML

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Function scope

When declaring variables within a function, using var is very similar to let.

They all have function scope:

Function myFunction () {

Var carName = "porsche"; / / function scope

}

Function myFunction () {

Let carName = "porsche"; / / function scope

}

Global scope

If you declare a declaration outside a block, then var and let are similar.

They all have a global scope:

Var x = 10; / / Global scope

Let y = 6; / / Global scope

Global variables in HTML

In the case of JavaScript, the global scope is the JavaScript environment.

In HTML, the global scope is the window object.

Global variables defined by the var keyword belong to the window object:

Example

Var carName = "porsche"

/ / the code here can use window.carName

The global variable defined by the let keyword does not belong to the window object:

Example

Let carName = "porsche"

/ / the code here cannot use window.carName

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