function shiftOpacity(id, millisec) { 
	//if an element is invisible, make it visible, else make it ivisible 
	if(document.getElementById(id).style.opacity == 0) { 
		opacity(id, 0, 100, millisec); 
	} else { 
		opacity(id, 100, 0, millisec); 
	} 
}

function blendimage(divid, imageid, imagefile, millisec) { 
	var speed = Math.round(millisec / 100); 
	var timer = 0; 
	 
	//set the current image as background 
	document.getElementById(divid).style.backgroundImage = "url(" + document.getElementById(imageid).src + ")"; 
	 
	//make image transparent 
	changeOpac(0, imageid); 
	 
	//make new image 
	document.getElementById(imageid).src = imagefile; 

	//fade in image 
	for(i = 0; i <= 100; i++) { 
		setTimeout("changeOpac(" + i + ",'" + imageid + "')",(timer * speed)); 
		timer++; 
	} 
}

function opacity(id, opacStart, opacEnd, millisec) { 
	//speed for each frame 
	var speed = Math.round(millisec / 100); 
	var timer = 0; 

	//determine the direction for the blending, if start and end are the same nothing happens 
	if(opacStart > opacEnd) { 
		for(i = opacStart; i >= opacEnd; i--) { 
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed)); 
			timer++; 
		} 
	} else if(opacStart < opacEnd) { 
		for(i = opacStart; i <= opacEnd; i++) 
			{ 
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed)); 
			timer++; 
		} 
	} 
} 

//change the opacity for different browsers 
function changeOpac(opacity, id) { 
	var object = document.getElementById(id).style; 
	object.opacity = (opacity / 100); 
	object.MozOpacity = (opacity / 100); 
	object.KhtmlOpacity = (opacity / 100); 
	object.filter = "alpha(opacity=" + opacity + ")"; 
}