//src - http://www.n2kdesign.co.uk/viewarticle.aspx?aID=56
//preload image
/*var collimg = new Image();
collimg.src = "collapse.gif";
var expimg = new Image();
collimg.src = "expand.gif";*/

function ShowHideLayer(boxID) {
	/* Obtain reference for the selected boxID layer and its button */
	var box = document.getElementById("box" + boxID);
	var boxbtn = document.getElementById("btn" + boxID);
	
	/* If the selected box is currently invisible, show it */
	if(box.style.display == "none" || box.style.display == "") {
		box.style.display = "block";
 		boxbtn.src = "assets/images/collapse.gif";
	}
	/* otherwise hide it */
	else {
		box.style.display = "none";
		boxbtn.src = "assets/images/expand.gif";
	}
}