It removes a class via javascript via Object prototype.

obj-removeClass.js

Object.prototype.removeClass = function (string) {
  var classList = this.className.split(' ');
  var classesToRemove = string.split(' ');

  for (var toRemove of classesToRemove) {
      var index = classList.indexOf(toRemove);
      if(index !== -1) {
          classList.splice(index, 1);
      }
  }

  this.classList = classList.join(' ');
};