var currentGalleryThumb = "button_1";
var selectedClass = "thumbnailson";
var fullImage = "fullGalleryImage";

function showFull(elm) {
	var currentThumb = document.getElementById(currentGalleryThumb);
//	alert('before, the classname is '+currentThumb.className);
	currentThumb.className = currentThumb.className.replace(""+selectedClass, "");
//	alert(currentThumb.className);
	elm.className+=" "+selectedClass;
	currentGalleryThumb = elm.id;
	
	var fullSize = document.getElementById(fullImage);
	var thumbsClicked = elm.getElementsByTagName('img');
	var thumbClicked = thumbsClicked[0];
	fullSize.src = thumbClicked.getAttribute('fullsrc');
}