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

	
	if (typeof current_opac=="undefined"){
		current_opac = opacStart;
		//alert(current_opac);
	}
	
	if(opacStart > opacEnd) {
		//alert ("opacStart > opacEnd");
		if (current_opac > 0) {
			//alert ("current_opac=" + current_opac + " > 0");
			chage_opac_to = current_opac - 20;
			setTimeout("opacity('"+id+"', "+opacStart+", "+opacEnd+", "+millisec+", "+chage_opac_to+")", 50);
		} else {
			return;	
		}
	} else if(opacStart < opacEnd) {
		if (current_opac < 100) {
			chage_opac_to = current_opac + 20;
			setTimeout("opacity('"+id+"', "+opacStart+", "+opacEnd+", "+millisec+", "+chage_opac_to+")", 50);
		} else {
			return;	
		}
	}
	
	changeOpac(chage_opac_to, id);
}

/*
source: http://www.brainerror.net/scripts_js_blendtrans.php
thank you
*/
/*
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++;
		}
		//document.getElementById(id).style.visibility = "visible";
	} else if(opacStart < opacEnd) {
		for(i = opacStart; i <= opacEnd; i++) {
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
			timer++;
		}
		//document.getElementById(id).style.visibility = "hidden";
	}
}
*/
//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 + ")";
}

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 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)
}