gistfile1.js

/**
 * Focusable element.
 *
 * @abstract
 * @class
 *
 * @constructor
 */
OO.ui.FocusableElement = function OoUiFocusableElement() {
	// add tabindex
};

/* Methods */

/**
 * Get focusable element.
 *
 * @return {jQuery} Focusable element
 */
OO.ui.FocusableElement.prototype.getFocusableElement = function () {
	throw new Error(
		'OO.ui.FocusableElement.getFocusableElement not implemented in this class:' + this.constructor
	);
};

/**
 * Show popup.
 */
OO.ui.FocusableElement.prototype.focus = function () {
	this.getFocusableElement()[0].focus();
};