var isDOM=document.getElementById?1:0;
var isIE=document.all?1:0;
var isNS4=navigator.appName=='Netscape'&&!isDOM?1:0;

function getRef(i, p) {
	p = !p ? document : p.navigator ? p.document:p;
	return isIE ? p.all[i]:isDOM ? (p.getElementById ? p : p.ownerDocument ).getElementById(i) : isNS4 ? p.layers[i] : null;
}

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 + ")";
	
	if(getRef(id).style.opacity == 0) getRef(id).style.display = 'none';	
	
}