const container = document.querySelector(".container") const containerWidth = document.querySelector(".container").clientWidth; console.log(containerWidth) const button = document.querySelector("button") let size = 16 button.addEventListener('click', () => { do { let gridSize = prompt("Please enter grid size: ") size = gridSize console.log(size) if (size > 100) { alert("Please enter number smaller than 100") } } while (size > 100); makeGrid(size) } ) function makeGrid(size) { container.innerHTML = "" for (let i=0; i < size * size; i++) { const squareBox = document.createElement("div") container.appendChild(squareBox) squareBox.setAttribute('class', 'grid') squareBox.style.width= containerWidth / size + "px";; squareBox.style.height= containerWidth / size + "px";; } const grid = document.querySelectorAll('.grid') for (i of grid) { i.addEventListener('mouseover', //e => e.target.classList.add('changecolor') e => e.target.style.backgroundColor = getRandomColor() ) } } makeGrid(size) function getRandomColor() { var letters = '0123456789ABCDEF'; var color = '#'; for (var i = 0; i < 6; i++) { color += letters[Math.floor(Math.random() * 16)]; } return color; }