var imageScrollStepSize			= 3;	// pixels
	var imageScrollStepTime			= 30;	// milliseconds
	var imageColObject;
	var imageColMeasureObject;
	var imageScrollInterval;
	var imageScrollViewableHeight	= 0;
	var imageScrollBandHeight		= 0;
	
	function initImageColInstance(){
		imageColObject				= document.getElementById('imageColContent');
		imageColMeasureObject		= document.getElementById('imageColContentMeasureElement');
		imageColObject.style.height	= imageColMeasureObject.offsetTop +'px';
		imageScrollViewableHeight	= parseInt(document.getElementById('imageCol').style.height);
		imageScrollBandHeight		= imageColMeasureObject.offsetTop;
	}
	
	function imageScroll(scrollDirection){
		if(typeof(imageColObject)!='object')
			initImageColInstance();
		
		window.clearInterval(imageScrollInterval);
		
		if(scrollDirection=='up'){
			imageScrollInterval			= window.setInterval('imageScrollUp()', imageScrollStepTime);
		}else if(scrollDirection=='down'){
			imageScrollInterval			= window.setInterval('imageScrollDown()', imageScrollStepTime);
		}else {
			window.clearInterval(imageScrollInterval);
		}
		
	}
	
	function imageScrollUp(){
		var currentTopPosition			= parseInt(imageColObject.style.top);
		if(currentTopPosition>((imageScrollBandHeight-imageScrollViewableHeight)*-1)){
			imageColObject.style.top	= currentTopPosition-imageScrollStepSize +'px';
		}else{
			window.clearInterval(imageScrollInterval);
		}
		
	}
	
	function imageScrollDown(){
		
		var currentTopPosition			= parseInt(imageColObject.style.top);
		if(currentTopPosition<0){
			imageColObject.style.top	= currentTopPosition+imageScrollStepSize +'px';
		}else{
			window.clearInterval(imageScrollInterval);
		}
	}