var scrollPct, prevStep, nextStep, interStep
steps = new Array();
steps[0] = new Array(128,128,128);
steps[1] = new Array(255,0,0);
steps[2] = new Array(255,255,0);
steps[3] = new Array(0,255,0);
steps[4] = new Array(0,255,255);
steps[5] = new Array(0,0,255);
steps[6] = new Array(255,0,255);
steps[7] = new Array(255,0,0);
steps[8] = new Array(255,255,255);
function newColor(chan) {
	var i=Math.floor(steps[prevStep][chan]+interStep*(steps[nextStep][chan]-steps[prevStep][chan]));
	return i;
	}
function scrollFunk() {
	scrollPct=(steps.length-1)*document.body.scrollTop/(document.body.scrollHeight-document.body.clientHeight);
	prevStep=Math.floor(scrollPct);
	nextStep=Math.ceil(scrollPct);
	interStep=scrollPct-prevStep;
	var newRGB="rgb("+newColor(0)+","+newColor(1)+","+newColor(2)+")";
	var invRGB="rgb("+(255-newColor(0))+","+(255-newColor(1))+","+(255-newColor(2))+")";
	if (document.body.style.scrollbarTrackColor != null) {
		document.body.style.scrollbarFaceColor=newRGB;
		document.body.style.scrollbarTrackColor=invRGB;
		}
	}
window.onscroll=scrollFunk;