//We wrap all the code in an object so that it doesn't interfere with any other code

var scroller = {
	init:   function() {

		//collect the variables
		scroller.docH = document.getElementById("content").offsetHeight;
		scroller.contH = document.getElementById("container").offsetHeight;
		scroller.scrollAreaH = document.getElementById("scrollArea").offsetHeight;

		//calculate height of scroller and resize the scroller div
		//(however, we make sure that it isn't to small for long pages)
		scroller.scrollH = (scroller.contH * scroller.scrollAreaH) / scroller.docH;
		//if(scroller.scrollH < 15) scroller.scrollH = 15;
		document.getElementById("scroller").style.height = Math.round(scroller.scrollH) + "px";
		// alert("scroller height="+document.getElementById("scroller").style.height);

		//what is the effective scroll distance once the scoller's height has been taken into account
		scroller.scrollDist = Math.round(scroller.scrollAreaH-scroller.scrollH);
		// alert("scrollDist="+scroller.scrollDist);

		// if scroller NOT needed then hide the scrollbar
		if (scroller.scrollDist <= 0) {
			document.getElementById("scrollArea").style.visibility = "hidden";
			document.getElementById("scroller").style.visibility = "hidden";
		}
		else {
			//make the scroller div draggable
			Drag.init(document.getElementById("scroller"),null,0,0,-1,scroller.scrollDist);

			//add ondrag function
			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";
			}
		}

	}
}