function dialog(id){
	document.getElementById("sol1a").style.backgroundImage="url('images/isol1.gif')";
	document.getElementById("sol2a").style.backgroundImage="url('images/isol2.gif')";
	document.getElementById("sol3a").style.backgroundImage="url('images/isol3.gif')";


	document.getElementById("sol1").className="hidden";
	document.getElementById("sol2").className="hidden";
	document.getElementById("sol3").className="hidden";

	
	
	}

function openD(id){
		element = document.getElementById(id);
		Aelement = document.getElementById(id+"a"); 

if(element.className == "hidden"){

		element.className = "visible";
		Aelement.style.backgroundImage="url('images/"+id+"-a.gif')"; 

	}
	}