function showSectionImg(elementId) {
	hideAll();
    var e = document.getElementById('img-' + elementId);
    //if (e == null) {alert ("showElement: Element \""+elementId+"\" not found."); return; }
	e.style.display = "block";
}

function showSectionImgHover(elementId) {
	hideAll();
    var e = document.getElementById('img-' + elementId +'-hover');
    //if (e == null) {alert ("showElement: Element \""+elementId+"\" not found."); return; }
	e.style.display = "block";
}

function restore() {
	hideAll();
}

function hideAll() {
	var e = getElementsByClassName('section-img');
	for (var i=0; i<e.length; i++) {
		e[i].style.display = "none";
	}

}

function getElementsByClassName(className, tag, elm){
	var testClass = new RegExp("(^|\\\\s)" + className + "(\\\\s|$)");
	var tag = tag || "*";
	var elm = elm || document;
	var elements = (tag == "*" && elm.all)? elm.all : elm.getElementsByTagName(tag);
	var returnElements = [];
	var current;
	var length = elements.length;
	for(var i=0; i<length; i++){
		current = elements[i];
		if(testClass.test(current.className)){
			returnElements.push(current);
		}
	}
	return returnElements;
}