What's the best way to make a script?
Object Oriented or just regular? Or does it really depend on what you make? What are the big benefits of OO? Less code, more structured, more re-usable?

I wanted to learn the OO way (because some people recommended me to), but I don't understand that much of it.
Does someone have a good tutorial?

I wrote a few test scripts, would it be better to do it the OO way or the way it is now?
And how would the script look like if this was in OO?

Code JavaScript:
<script type="text/javascript">
function doEffect(){
var obj;
var TimerID;
var TimerIDTwo;
var interval = 50;
var originwidth = 50;
var changinwidth = 50;
var changedwidth;
var speed = 8;
var theElem = document.getElementsByTagName('li');
    for (var i=0; i<theElem.length; i++){
    theElem[i].onclick = startBreder;
  function startBreder(){
  obj = this;
  TimerID = setTimeout(function(){maakBreed(obj);},interval);
  changinwidth = originwidth;
  TimerID = setTimeout(function(){maakKort(obj);},interval);
  changedwidth = originwidth;
  function maakBreed(){
   changinwidth = changinwidth+speed;
    obj.style.width = changinwidth + 'px';
    TimerID = setTimeout(function(){maakBreed(obj);},interval);
   changedwidth = changinwidth;
  function maakKort(){
    changedwidth = changedwidth-speed;
    obj.style.width = changedwidth + 'px';
    TimerID = setTimeout(function(){maakKort(obj);},interval);
window.onload = doEffect;