/***********************************
	 ****     OPACITY FUNCTIONS      ***
	 ***********************************/
	 
	// opacity(id, opacStart, opacEnd, millisec)
	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++;
			}
		} 
	}

	// changeOpac(opacity, id)
	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 + ")";
		/*if(opacity > 0)
			object.display="block";
		else
			object.display="none";*/
	}
	
	// shiftOpacity(id, millisec)
	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);
		}
	}
	
	// blendimage(divid, imageid, imagefile, 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++;
		}
	}
	
	// currentOpac(id, opacEnd, millisec) 
	function currentOpac(id, opacEnd, millisec) {
		//standard opacity is 100
		var currentOpac = 100;
		
		//if the element has an opacity set, get it
		if(document.getElementById(id).style.opacity < 100) {
			currentOpac = document.getElementById(id).style.opacity * 100;
		}
	
		//call for the function that changes the opacity
		opacity(id, currentOpac, opacEnd, millisec)
	}