function PanelToggle(id, color)
{
    var box = document.getElementById( id );
    var header = document.getElementById( "header." + id );

    if ( box != null ) {
	if ( box.style.display == "block" ) {
		opacity(id, 100, 0, 500);
		header.style.background = "url('/i/hb." + color + ".down.jpg')";
	} else {
		box.style.display = "block";
		opacity(id, 1, 100, 50);
		header.style.background = "url('/i/hb." + color + ".up.jpg')";
	}
    }
}

<!--StartFragment -->
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 ( opacity == 0 ) {
	    var block = document.getElementById( id );
		block.style.display = "none";
	}
	   
}