A function is the main building block of the JavaScript program. We can call the function many times without any repetition of code. Functions are designed to perform a particular task.

Advantage

• Code reusability
• Less code
• Easy to readable

Syntax

Explanation

Function Declaration

• Function declaration starts with a function keyword
• Then, goes the name of the function
• Then, the parameter of the function between two paranthese, separated by a comma.
• Then, we can write code between two curly braces called the function body
• And now call the function with their function name.

Hoisting in function

When we declare a variable inside a function, that variable is only visible inside the local scope.

If we try to access outside of the function, it throws an error message into the console.

If a variable declares in global scope then, we can access that variable inside any function body.

We can update the global variables from the function body with var and let keywords.

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