function MyScroll (o)
{
this.z=document.getElementById(o);
this.n=document.getElementById(o+'W');
this.s=this.n.style;
this.l=0;//stoper
this.y=0;//pozycja
this.w=this.n.offsetHeight-this.z.offsetHeight;
this.obj=o+"Ob";
eval(this.obj+"=this");

this.przesun=ScrollPrzesun;
this.stop=ScrollStop;
this.krok=ScrollKrok;

function ScrollPrzesun(k){
  this.stop();
  this.l=setInterval(this.obj+'.krok('+k+')',50);
}
function ScrollStop(){
clearInterval(this.l)
}
function ScrollKrok(k){
if(k<0 && this.y<=0)
{
this.y-=k;
this.s.top=this.y;
}else if(k>0 && this.y >-this.w){
this.y-=k;
this.s.top=this.y;
}
}
}