/**
 * Wechselt das Bild.
 * @param imageID {string} HTML-ID des Bildes
 * @param imageName {string} Basisname des Bildes (name.png => name_over.png)
 * @param eventName {string} Ereignis (over, out)
 */
function toggleImage(imageID, imageName, eventName) {
	
	var imageElement = document.getElementById(imageID);
	
	if (imageElement && imageElement.src) {
	
		switch(eventName) {
			case "over":
				imageElement.src = imageElement.src.replace(imageName, imageName + "_over")		
				break;
			case "out": 
				imageElement.src = imageElement.src.replace(imageName + "_over", imageName)
				break;
		}
	}
}

function doRollover(imageID, imageName) {
	toggleImage(imageID, imageName, "over")
}

function doRollout(imageID, imageName) {
	toggleImage(imageID, imageName, "out")
}

function removeEmptyListItems() {
	
	var forms = document.getElementsByTagName("form");
	
	for(var i = forms.length-1; i>=0; --i) {
		var elements = forms[i].getElementsByTagName("li");
		if(elements) {
			for(var i = elements.length-1; i>=0; --i) {
				var element = elements[i];
				if ((element && element.hasChildNodes) && !element.hasChildNodes()) {
					var parentNode = element.parentNode;
					parentNode.removeChild(element);
					if (!parentNode.hasChildNodes()) {
						parentNode.parentNode.replaceChild(document.createTextNode("-"), parentNode);
					}
				}
			}
		}	
	}
}