function Marquee(box,content,speed,dirc,coefOverSpeed){
  //ini les variables
  this.box=$(box);
  this.content=$(content);
  this.speed=speed || 1;
  this.dirc=dirc || 'top';
  this.coefDirc=1;
  this.coefOverSpeed=coefOverSpeed || 3;
  this.inverseDirc=(this.dirc=='bottom' || this.dirc=='right');
  var horizontalDirc=(this.dirc=='bottom' || this.dirc=='top');
  
  //on repositionne les élements + cache les scrolls 
  this.box.style.overflow='hidden';
  this.box.style.position='relative';//ie7 bug
  this.content.style.position='relative';
  
  //calcule la dimension du conteneur  + la dimention du contenue 
  var boxDim=this.box['client'+(horizontalDirc?'Height':'Width')];
  var contentDim=this.content['offset'+(horizontalDirc?'Height':'Width')];
  
  //on retient la moitier de la dim , pour le mouse over
  this.middleDim=boxDim/2;
  
  //on definit las position max et de départ
  this.maxDim=this.inverseDirc?-boxDim:-contentDim;
  this.startStep=this.inverseDirc?contentDim:boxDim;
  this.currentStep=this.startStep;
  
  //ajoutes les evenemnts

  
  this.interval=setInterval(this.interval.bind(this),35);
  
  this.eventUnload=this.unload.bindAsEventListener(this);
  Event.observe(window,'unload',this.eventUnload.bind(this));
}
Marquee.prototype={
   onMouseout : function(e){
      Event.stopObserving(this.box,'mousemove',this.eventMouseMove);
      this.coefDirc=1;
   },
   onMouseover : function(e){
       var dim=Element.viewportOffset(this.box);
       if(this.dirc=='top' || this.dirc=='bottom'){
         this.coor=[dim[1],dim[1]+this.box.clientHeight];
       }else this.coor=[dim[0],dim[0]+this.box.clientWidth];
       this.mouseMove(e);
       this.eventMouseMove=this.mouseMove.bindAsEventListener(this);
       Event.observe(this.box,'mousemove',this.eventMouseMove);
   },
   interval : function(){
     var acc=this.speed*this.coefDirc;
     $(this.content).style[this.dirc]=this.currentStep-acc+'px';
     this.currentStep-=acc;
     if(this.currentStep>this.startStep)
        this.currentStep=this.maxDim;
     if(this.inverseDirc){
        if(this.currentStep<this.maxDim)
           this.currentStep=this.startStep;
     }else{
        if(this.currentStep<this.maxDim)
           this.currentStep=this.startStep;
     }
   },
   mouseMove:function(e){
      if(this.dirc=='top' || this.dirc=='bottom'){
         var mouseCoor=Event.pointer(e).y;
      }else var mouseCoor=Event.pointer(e).x;
      var inverseCoeff=(mouseCoor-this.coor[0]>this.coor[1]-mouseCoor);
      var coef=inverseCoeff?this.coor[1]-mouseCoor:mouseCoor-this.coor[0];
      this.coefDirc=((this.middleDim-coef)/this.middleDim)*this.coefOverSpeed;
      if(inverseCoeff)this.coefDirc=-this.coefDirc;
      if(this.inverseDirc)this.coefDirc=-this.coefDirc;
   },
   unload : function(){
      clearInterval(this.interval);
      Event.stopObserving(this.box,'mouseover',this.eventOver);
      Event.stopObserving(this.box,'mouseout',this.eventOut);
      Event.stopObserving(window,'unload',this.eventUnload.bind(this));    
   }
}