function toggleVisibility(identifier) {
	var elm = document.getElementById(identifier);
	if(elm.className == "invisible") {
		elm.className = "";
	} else {
		elm.className = "invisible";
	}      
}   

function popup(winlocation) {
  	var winwidth = screen.width;
  	var winheight = screen.height;
	newwin = window.open(winlocation, "_blank", "toolbar=yes, location=yes, menubar=yes, resizable=yes");
}