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.eventOver=this.onMouseover.bindAsEventListener(this);
Event.observe(this.box,'mouseover',this.eventOver);

this.eventOut=this.onMouseout.bindAsEventListener(this);
Event.observe(this.box,'mouseout',this.eventOut);

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));
}
}