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JavaScript Function Scope | Basics

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In JavaScript, there is a function scope concept, where each function creates a new scope. Variables that are declared inside a function are called local variables and in the function scope.

// The following variables are defined in the global scope
var num1 = 20,
    num2 = 3,
    name = 'Chamakh';

// This function is defined in the global scope
function multiply() {
  return num1 * num2;
}

multiply(); // Returns 60

// A nested function example
function getScore() {
  var num1 = 2,
      num2 = 3;

  function add() {
    return name + ' scored ' + (num1 + num2);
  }

  return add();
}

getScore(); // Returns "Chamakh scored 5"

Note: A variables declared with let and const in a function are pretty similar when using var inside a function.

JavaScript Function Scope

Simple example code variables defined inside a function cannot be accessed from anywhere outside the function, because the variable is defined only in the scope of the function.

However, a function can access all variables and functions defined inside the scope in which it is defined.

<!DOCTYPE html>
<html>
<body>
  <script>    
    function myFunction() {
      // Function Scope variables
      var car1 = "Volvo";  
      var car2 = "BMW";
      var car3 = "Tesla"; 

      console.log(car1,car2,car3)
    }

    myFunction();
    console.log(car1,car2,car3)
  </script>  

</body>
</html>

Output:

JavaScript Function Scope

Do comment if you have any doubts or suggestions on this Js scope topic.

Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.

OS: Windows 10

Code: HTML 5 Version

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