document.addEventListener('mouseover', addBorder) function addBorder(e) { document.querySelectorAll('*').forEach(el => el.style.border = '') e.target.style.border = '10px solid lime' }
document.addEventListener('mouseover', addBorder) function addBorder(e) { document.querySelectorAll('*').forEach(el => el.style.border = '') e.target.style.border = '10px solid lime' }