if (!document.getElementById)
    document.getElementById = function() { return null; }

function getContentWidth(el){
     //var tmp=el.style.overflow;
     //el.style.overflow='auto';
     var w=el.offsetWidth;
     //el.style.overflow=tmp;
     return w;
}

function verifyCompatibleBrowser(){
  this.ver=navigator.appVersion;
  this.dom=document.getElementById?1:0;
  this.ie5=(this.ver.indexOf("MSIE 5")>-1 && this.dom)?1:0;
  this.ie4=(document.all && !this.dom)?1:0;
  this.ns5=(this.dom && parseInt(this.ver) >= 5) ?1:0;
  this.ns4=(document.layers && !this.dom)?1:0;
  this.bw=(this.ie5 || this.ie4 || this.ns4 || this.ns5);
  return this;
}

bw=new verifyCompatibleBrowser();

var speed=50;

var loop, timer;

function ConstructObject(obj,nest){
  nest=(!nest) ? '':'document.'+nest+'.';
  this.el=bw.dom?document.getElementById(obj):bw.ie4?document.all[obj]:bw.ns4?eval(nest+'document.'+obj):0;
  this.css=bw.dom?document.getElementById(obj).style:bw.ie4?document.all[obj].style:bw.ns4?eval(nest+'document.'+obj):0;
  this.scrollWidth=bw.ns4?this.css.document.width:getContentWidth(this.el);
  this.clipWidth=bw.ns4?this.css.clip.width:this.el.offsetWidth;
  this.up=MoveAreaUp;this.down=MoveAreaDown;
  this.MoveArea=MoveArea; this.x; this.y;
  this.obj = obj + "Object";
  eval(this.obj + "=this");
  return this;
}

function MoveArea(x,y){
  this.x=x;this.y=y;
  this.css.left=this.y + "px";
  decalage = -this.y;
  this.css.top=this.x + "px";
}

function MoveAreaDown(move){
  if(this.y>-this.scrollWidth+objContainer.clipWidth){
    this.MoveArea(0,this.y-move);
    if(loop) setTimeout(this.obj+".down("+move+")",speed);
  }
}
function MoveAreaUp(move){
  if(this.y<0){
    this.MoveArea(0,this.y-move);
    if(loop) setTimeout(this.obj+".up("+move+")",speed);
  }
}

function PerformScroll(speed){
  if(initialised){
    loop=true;
    if(speed>0) objScroller.down(speed)
    else objScroller.up(speed);
  }
}

function CeaseScroll(){
  loop=false;
  if(timer) clearTimeout(timer);
}
var initialised;

function InitialiseScrollableArea(){
  if (document.getElementById("scrollable")) {
    objContainer=new ConstructObject('scrollable');
    objScroller= new ConstructObject('scrolling','scrollable');
    objScroller.MoveArea(0,0);
    objContainer.css.visibility='visible';
    initialised=true;
  }
}