How does JavaScript Variable Scope work?

JavascriptWeb DevelopmentFront End Technology

The scope of a variable is the region of your program in which it is defined. JavaScript variables have only two scopes.

  • Global Variables − A global variable has a global scope which means it can be defined anywhere in your JavaScript code.
  • Local Variables − A local variable will be visible only within a function where it is defined. Function parameters are always local to that function.

Let’s see how the scope of variables works in JavaScript.

Within the body of a function, a local variable takes precedence over a global variable with the same name. If you declare a local variable or function parameter with the same name as a global variable, you effectively hide the global variable.


   <body onload = checkscope();>
            var myVar = "global"; // Declare a global variable
            function checkscope( ) {
               var myVar = "local"; // Declare a local variable
Updated on 13-Jun-2020 07:41:31