closure in javascript.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Closure</title>
</head>
<body>
    <script>
        // A closure is a fucntion having access to the parent scope. it preserve the data form outside.
        // A closure is an inner fucntion that has access to the outer (enclosing) function's variables.
        // for every closure we have three scopes.
        // 1. local scope (own scope) 2. outer function scope 3. Global scope

        // example
        var a = 10;
        function x(){
            var b = 60;
            document.write(b +"<br>");
            document.write(a +"<br>");

        }
        x();
        // example 2 
        function test(){
        var c = "local variable outer function";
        document.write(c +"<br>");
        function inner(){
            var d = "local variable inner fucntion";
            document.write(d + "<br>");
        }
        inner();
        }
        
        test();
       
    </script>
</body>
</html>