function showPicture(whichpicture) {
	var source = whichpicture.getAttribute("href");
	var placeholder = document.getElementById("placeholder");
	placeholder.setAttribute("src",source);
	
	var source2 = whichpicture.getAttribute("alt");
	var placeholder2 = document.getElementById("placeholder2");
// clear current content
	while(placeholder2.hasChildNodes()){
		placeholder2.removeChild(placeholder2.firstChild);
	};
// add content
	placeholder2.appendChild(document.createTextNode(source2));
}