var scroller = {
  init:   function() {
    scroller.docH = document.getElementById("content").offsetHeight;
    scroller.contH = document.getElementById("container").offsetHeight;
    
	//Altura do container
	if(scroller.docH > scroller.contH){
		document.getElementById("scrollArea").style.display = "block";
    	scroller.scrollAreaH = document.getElementById("scrollArea").offsetHeight;
		
		//Altura da imagem do dragger
	    scroller.scrollH = document.getElementById("dragger").height;
		
	    document.getElementById("scroller").style.height = Math.round(scroller.scrollH) + "px";    
	    scroller.scrollDist = Math.round(scroller.scrollAreaH-scroller.scrollH);
	    Drag.init(document.getElementById("scroller"),null,0,0,-1,scroller.scrollDist);    
	    document.getElementById("scroller").onDrag = function (x,y) {
	      var scrollY = parseInt(document.getElementById("scroller").style.top);
	      var docY = 0 - (scrollY * (scroller.docH - scroller.contH) / scroller.scrollDist);
	      document.getElementById("content").style.top = docY + "px";
	    }
  	} else {
		document.getElementById("scrollArea").style.display = 'none';
	}
  }
}
onload = scroller.init;