script.js

function randomInteger(max) {
    return Math.floor(Math.random()*(max + 1));
}

function randomRgbColor() {
    let r = randomInteger(255);
    let g = randomInteger(255);
    let b = randomInteger(255);
    return [r,g,b];
}

function randomHexColor() {
    let [r,g,b] =randomRgbColor();

    let hr = r.toString(16).padStart(2, '0');
    let hg = g.toString(16).padStart(2, '0');
    let hb = b.toString(16).padStart(2, '0');

    return "#" + hr + hg + hb;
}

function changeColor() {
  let hex = randomHexColor();
  document.getElementById('color').value = hex;
  document.getElementById('text').innerHTML = hex;
}

function clickHandler(event) {
  changeColor();
  event.preventDefault();
}

document.addEventListener('click', clickHandler);

changeColor();