/**
 * @namespace anim
 */
    
/**
 * @method anim.fadein(1)
 * @desc Show the nodelist elements by fading them to opaque.
 * @since 1.0
 * 
 * @param {number}   [duration=400] How long the animation will run.
 * @param {function} [callback]     Called once the animation is complete.
 * 
 * @returns {this}
 */

/**
 * @method anim.fadein(2)
 * @desc Show the nodelist elements by fading them to opaque.
 * @since 1.4.3
 * 
 * @param {number}   [duration=400] How long the animation will run.
 * @param {string}   [easing=swing] The easing function for the transition.
 * @param {function} [callback]     Called once the animation is complete.
 * 
 * @returns {this}
 */