/**
                            * Get input string from user
                            * Controller Function
                            */
                            function getValue(){
                                document.getElementById('alert').classList.add('invisible');

                                let userString = document.getElementById('userString').value;

                                let revString = reverseString(userString);

                                displayString(revString);
                            }

                            /**
                            * Reverse the string
                            * Logic Function
                            */
                            function reverseString(string){
                                let revString = [];
                                
                                for (let index = string.length-1; index >= 0; index--) {
                                    revString += string[index];
                                }

                                return revString;
                            }

                            /**
                            * Display message with reversed string
                            * View Function
                            */
                            function displayString(string){
                                //write message to page 
                                document.getElementById('message').innerHTML = `Your string reversed is ${string}`;

                                //show the alert box
                                document.getElementById('alert').classList.remove('invisible');
                            }
                        
                    

Hello World

The code is contained within a function

"helloWorld" is a function that displays an alert