callback.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <p>&#128512;</p> 
    <script>
        function parent(name){
            console.log("Hello, " + name);
        }

        function child(callback){
            callback("abc xyz");
        }

        child(parent);




        console.log("");
        function a(){
            console.log("Parent Function");
            console.log(callback(a,b));
        }
        function b(){
            return a + b;
        }
        a(b, 2, 3);

    </script>
</body>
</html>