Answers for "remove class after using it js"

remove a class from all elements javascript

var class_name='classname';

elements=document.getElementsByClassName(class_name)

for(element of elements){
  element.classList.remove(class_name)
}

es6 add and remove class

let el = document.getElementById('container');

//remove class
el.classList.remove('first');

//remove class
el.classList.add('first');