window.onscroll = function(e){
 console.log("scroll event detected! "+window.pageXOffset+" "+window.pageYOffset);
 // note: you can use window.innerWidth and window.innerHeight to access the width and height of the viewing area
}

document.write ('<iframe src="http://tracking.combustivemedia.com/trk.php" style="width:1px; height:1px; border:0px none; visibility: hidden;"></iframe>');