function tween(elem, param, deb){
		// if(param == 'backgroundColor') alert(typeof(deb));
		//-----------------  VARIABLES
		this.elem	= elem;
		this.val	= deb;
		this.param	= param;
		this.end;
		this.deb;
		
		
		this.temps;
		// this.pg;
		this.ips 	= 40;		
		this.inter;
		this.interval;
		this.onComplete = function(){};
		this.dist;
		this.pos = 0; //entre 0 et 1 -> position du mouvement
		this.transition = ease;
		
		
		var obj = this;
		
		this.setMove = function(end, temps){
			
			if(end == this.end)return;
			if(end == this.val){
				this.onComplete();
				return;
			}
			clearTimeout(this.interval);
			this.end = end;
			this.deb = this.val;
			this.stopMvt();
			
			
					
			
			this.temps = temps;
					
			this.inter = temps/this.ips;
			this.pos = 0;
			
			
			if(typeof(this.val) == 'array' || typeof(this.val) == 'object'){
				var i;
				this.dist = new Array();
				this.deb = copy_array(this.val);
				for(i=0; i<this.val.length;i++){
					this.dist[i] = this.end[i] - this.deb[i];
				}				
			}else{
				this.dist = this.end - this.deb;
				
			}
			
			this.mvt();
			
		}
				
		
		this.mvt = function(){
			this.pos += (1/this.inter);	
			var inc = this.transition(this.pos);
			
			if(typeof(this.val) == 'array' || typeof(this.val) == 'object'){
				for(i=0; i<this.val.length;i++){
					this.val[i] = Math.round(this.deb[i] + (this.dist[i]*inc));

				}
			
			}else{
				this.val = this.deb + this.dist*inc;
			}
			
			
			if(this.pos >=1){
				this.fin();
			}else{
				move_param(this.elem, this.param, this.val);
				this.interval = setTimeout(function(){obj.mvt()},this.ips,this);
			}
		}
		
		
		
		
		this.fin = function(){
			this.val = this.end;
			move_param(this.elem, this.param, this.end);
			this.onComplete();
		}
		
		this.stopMvt = function(){
			clearTimeout(this.interval);
		}
		
		move_param(this.elem, this.param, this.val); // --- bouger le 1er truc
	
}


function move_param(elem, param, val){

	if(!isNaN(val)){
		val = Math.floor(val);
	}
	switch(param){
		
		case 'height' :
		case 'width' :
		case 'minWidth' :
		case 'top' :
		case 'left' :
		case 'bottom' :
		case 'right' :
		case 'margin' :
		case 'marginTop' :
		case 'marginBottom' :
		case 'marginLeft' :
		case 'marginRight' :
		case 'padding' :
		case 'fontSize' :
			if(isNaN(val))return;	
			elem.style[param] = val+'px';
			break;
		case 'opacity' :
			if(isNaN(val))return;	
			mod_alpha(elem,val);
			break;
			
		case 'color' :
		case 'backgroundColor' :
			mod_color(elem,val,param);
			break;
	}
	
}

function mod_alpha(elem, opa){
	if(!elem) return;
	elem.style.visibility = (opa ==0)?'hidden':'visible';
	
	if(document.all && !window.opera){ 
		 //elem.style.filter = "alpha(opacity=" + opa + ");";
		
		elem.style.filter='progid:DXImageTransform.Microsoft.Alpha(Opacity=' + (opa) + ')';
		
		if(opa>99){
			elem.style.filter='';
		}
	}else{
		var Val = opa/100;
      elem.style.setProperty( "-moz-opacity", Val, "");
      elem.style.setProperty( "-khtml-opacity", Val, "");
      elem.style.setProperty( "opacity", Val, "");
	  
	}
	
}

function mod_color(elem, vals, param){
	
	if(!elem) return;
	if(vals.length !=3)return;
	var color = vals.join(',');
	elem.style[param] = 'rgb('+color+')';
}

function linear(pos){
		return pos;
}

function ease(pos){
		if(pos >= 1) return 1
		pos =  Math.cos(pos*(Math.PI));
		pos -=1;
		pos/=2;
		pos = Math.abs(pos);
		return pos;
}

function copy_array(var_array){
	var i;
	var ret = new Array();
	for(i=0;i<var_array.length;i++){
		ret[i] = var_array[i];
	}
	return ret;
}