code: function removeClasses(el, classes) {
    var newClasses = convertToArray(classes);
    var classList;
  
    if (el.className instanceof SVGAnimatedString) {
      classList = convertToArray(el.className.baseVal);
    } else {
      classList = convertToArray(el.className);
    }
  
    newClasses.forEach(function (newClass) {
      var index = classList.indexOf(newClass);
  
      if (index !== -1) {
        classList.splice(index, 1);
      }
    });
  
    if (el instanceof SVGElement) {
      el.setAttribute('class', classList.join(' '));
    } else {
      el.className = classList.join(' ');
    }
  }
docs: Remove classes from an element.
  It uses el.className rather than classList in order to be IE friendly.
  @export
  @param {any} el The element to remove the classes from.
  @param {any} classes List of space separated classes to be removed from the element.