Alter Carousel Script for Next Previous

I’m trying to slightly alter the script found here, [url]http://www.adrianhodge.com/web-design/mootools-horizontal-div-slider-121/[/url].

What i want to do is make the carousel work on a Next/Previous feature versus a 1, 2, 3 method. I tried to do it myself but found i was was just going in circles and nothing was working. Any help is appreciated. I have listed below the only parts that should matter.

Javascript

[CODE]<script language=”Javascript”>
<!–
function slideFolio(col){
var x = ((col-1)*-505)
var folioChange = new Fx.Tween(‘folio’, {duration:2000});
folioChange.start(‘left’,x);
var cur = “trigger”+col;
$(cur).addClass(‘current’);

for (i=1;i<=8;i++){
var loopLI = “trigger”+i;
if (cur==loopLI){}else{
$(loopLI).removeClass(‘current’);
}
}
}
//–>
</script>[/CODE]

HTML

[CODE]<ul class=”nums”>
<li id=”trigger1″ class=”current”><a href=”javascript:slideFolio(1);” class=”liinternal”>1</a></li>
<li id=”trigger2″><a href=”javascript:slideFolio(2);” class=”liinternal”>2</a></li>
<li id=”trigger3″><a href=”javascript:slideFolio(3);” class=”liinternal”>3</a></li>
</ul>[/CODE]

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