const signs = document.querySelectorAll('x-sign') const randomIn = (min, max) => ( Math.floor(Math.random() * (max - min + 1) + min) ) const mixupInterval = el => { const ms = randomIn(2000, 4000) el.style.setProperty('--interval', `${ms}ms`) } signs.forEach(el => { mixupInterval(el) el.addEventListener('webkitAnimationIteration', () => { mixupInterval(el) }) })