useless piece of code

presentation.js

void function(){
	"use strict"
	var bean = require('bean')
		, KeySpline = require('./keyspline.js')
		, splineFrom = new KeySpline(0.93,0.01,0.12,0.99)
		, splineTo = new KeySpline(0.93,0.01,0.12,0.99)
		, $ = function(id){ return document.getElementById.call(document, id) }
		, $$ = function(selector, parent){ parent = parent || document; return parent.querySelectorAll.call(parent, selector) } 
		, lock = false
		, slideshow , slides , steps, target
		, sliderStep = 1
		;

	function createFader(elem, opacity){
		return function(){elem.style.opacity = opacity}
	}

	function delClass(elem, classname){
		elem.className = elem.className.replace( new RegExp('/(?:^|\s)'+classname+'(?!\S)/g') , '' )
	}

	function setClass(elem, classname){
		elem.className = elem.className + ' '+classname
	}

	function switchClass(fromelem, toelem, classname){
		fromelem.className = fromelem.className.replace( new RegExp('\\b'+classname+'\\b', 'g') , '' )
		toelem.className = toelem.className + ' ' +classname
	}

	function crossfade(to){
		var step
			, from = $$('img.active', slideshow)[0]
			;

		if ( ! lock && from != to ) {
			lock = true
			from.style.opacity = 1
			to.style.opacity = 0
			to.style.display = 'block'
			console.log(target)
			switchClass($$('.active',$$('.control', slideshow )[0])[0], target, 'active')

			for ( step = 1; step < 21; step++ ) {
				setTimeout( createFader(from, 1 - splineFrom.get(step/20)) , 50*step )
				setTimeout( createFader(to, splineTo.get(step/20)), 50*step )
				if ( step == 20 ) {
					setTimeout( function(){
						from.style.display = 'none'
						switchClass(from, to, 'active')
						lock = false
					}, 50*step) 
				}
			}
		}
	}
		
	function startSlider(){
		sliderStep = sliderStep == 4 ? 1 : sliderStep + 1
		target = $('control'+sliderStep)
		crossfade($('sl'+sliderStep))
		setTimeout(startSlider,7000)
	}

	bean.on(window, 'load', function(){
		slideshow = $('slideshow')
		slides = $('slides')
		steps = $$('.steps img', slides )
		
		setTimeout(startSlider,7000)

		bean.on($$('#slides .control', slideshow)[0], 'click', '.switch', function(event){
		
			var sl = parseInt((target = event.target).getAttribute('data-sl'))
				;
			
			event.stop()
			crossfade($('sl'+sl))

		})


	})
}()