code

                    
                        // controller function
                        function getValues() {
                            let fizz = document.getElementById('fizz').value;
                            let buzz = document.getElementById('buzz').value;
                            let endValue = document.getElementById('endValue').value;
                        
                        
                            // parse inputs as numbers
                            fizz = parseInt(fizz);
                            buzz = parseInt(buzz);
                            endValue = parseInt(endValue);
                        
                            fizzbuzz = fizz * buzz;
                        
                            // verify inputs are numbers
                            if (Number.isInteger(fizz) && Number.isInteger(buzz) && Number.isInteger(endValue) && endValue < 5001) {
                            
                                // if so, generate numbers
                                let fizzBuzzArray = generateFizzBuzz(fizz, buzz, endValue);
                            
                                // display on page
                                displayFizzBuzz(fizzBuzzArray);
                            
                            } else {

                                // else, notify user
                            
                                Swal.fire(
                                    {
                                        icon: 'error',
                                        title: 'Oops!',
                                        text: 'Ending value must be 5000 or less!'
                                    }
                                );
                            }
                        }

                        // logic function
                        function generateFizzBuzz(fizz, buzz, end) {
                        
                            let numbers = [];
                        
                            for (let i = 1; i <= end; i++) {

                                if (i % fizz == 0 && i % buzz == 0) {
                                    sub = 'FizzBuzz';
                                    numbers.push(sub)
                                } else if (i % fizz == 0) {
                                    sub = 'Fizz';
                                    numbers.push(sub)
                                } else if (i % buzz == 0) {
                                    sub = 'Buzz';
                                    numbers.push(sub)
                                } else {
                                    numbers.push(i);
                                }

                            }
                            return numbers;
                        }

                        // display function
                        function displayFizzBuzz(fizzBuzzArray) {
                            let appBody = document.getElementById('results');
                        
                            let appHTML = "";
                        
                            for (let i = 0; i < fizzBuzzArray.length; i++) {
                                let value = fizzBuzzArray[i];
                            
                                className = '';
                            
                                if (fizzBuzzArray[i] == 'FizzBuzz') {
                                    className = 'fizzbuzz'
                                } else if (fizzBuzzArray[i] == 'Fizz') {
                                    className = 'fizz'
                                } else if (fizzBuzzArray[i] == 'Buzz') {
                                    className = 'buzz'
                                }
                            

                                let appRow = `<div class="col py-2 ${className}">${value}</div>`;
                            
                            
                                appHTML += appRow
                            }
                        
                            appBody.innerHTML = appHTML;
                        }