code: function ArrayField(type, options) {
    Field.call(this, type, options);
    this.options = options;
  
    this._onAdd = this._onAdd.bind(this);
    this.members = [];
  
    // <div class=gcliArrayParent save="${element}">
    this.element = util.createElement(this.document, 'div');
    this.element.classList.add('gcli-array-parent');
  
    // <button class=gcliArrayMbrAdd onclick="${_onAdd}" save="${addButton}">Add
    this.addButton = util.createElement(this.document, 'button');
    this.addButton.classList.add('gcli-array-member-add');
    this.addButton.addEventListener('click', this._onAdd, false);
    this.addButton.textContent = l10n.lookup('fieldArrayAdd');
    this.element.appendChild(this.addButton);
  
    // <div class=gcliArrayMbrs save="${mbrElement}">
    this.container = util.createElement(this.document, 'div');
    this.container.classList.add('gcli-array-members');
    this.element.appendChild(this.container);
  
    this.onInputChange = this.onInputChange.bind(this);
  
    this.onFieldChange = util.createEvent('ArrayField.onFieldChange');
  }
docs: Adds add/delete buttons to a normal field allowing there to be many values
  given for a parameter.