// Défilement 4 directions multiple
function Defilant(id, pos_init, pos_min, pos_max, delta, direction) {
   this.id          = id;
   this.element     = document.getElementById(id);
   this.pos_init    = pos_init;
   this.pos_min     = pos_min;
   this.pos_max     = pos_max;
   this.pos_current = pos_init;
   this.delta       = delta;
   this.direction   = direction;
}

Defilant.prototype.defile = function() {
   if (!this.element) {
      this.element = document.getElementById(this.id);
   }
   if (this.element) {
      if(this.direction == 'vertical'){
if(this.pos_current < (this.pos_min - this.element.offsetHeight) ){
            this.pos_current = this.pos_init;
         } else if (this.pos_current > this.pos_max ) {
            this.pos_current = this.pos_init - this.element.offsetHeight;
         } else {
            this.pos_current += this.delta;
         }
         this.element.style.top = this.pos_current+"px";
      } else if(this.direction == 'horizontal') {
         if(this.pos_current < (this.pos_min - this.element.offsetWidth) ){
            this.pos_current = this.pos_init;
         } else if (this.pos_current > this.pos_max ) {
            this.pos_current = this.pos_init - this.element.offsetWidth;
         } else {
            this.pos_current += this.delta;
         }
         this.element.style.left = this.pos_current+"px";
      }
   }
}