Select Class with JavaScript – getElementsByClassName

const myList = document.getElementsByTagName('li');
 for (let i = 0; i < myList.length; i += 1) {
   myList[i].style.color = 'purple';
 }
 const errorNotPurple = document.getElementsByClassName('error-not-purple');
 for (let i = 0; i < errorNotPurple.length; i += 1) {
   errorNotPurple[i].style.color = 'red';
 }