function extractStuff(theString,theStart,theEnd) {
	stringArray = theString.split(theStart);
    arrayLength = stringArray.length - 1; 
    var thisFilename = stringArray[arrayLength];
    
    filenameArray = thisFilename.split(theEnd);
    thisFilename = filenameArray[0];
    
    return(thisFilename);
}

function extractFilename() {
    var thisUrl = window.location.href;    
    thisFilename = extractStuff(thisUrl,"/",".");
    
    if(!thisFilename) {
        thisFilename = "index";
    }
    
    return(thisFilename);
}

function extractImgName(theElement) {
	theFilename = extractStuff(theElement.src,"/","_");
	return(theFilename);
}

function cleanHref() {
	windowHref = window.location.href;
	windowHrefArray = windowHref.split(".php");
	windowHref = windowHrefArray[0] + ".php";
	
	return(windowHref);
}

function naviOver(theElement) {
	theImgName = extractImgName(theElement);
	theElement.src = "images/navi/"+theImgName+"_act.gif";
}

function naviOut(theElement) {
	if(theElement.parentNode.href != cleanHref()) {
		theImgName = extractImgName(theElement);
		theElement.src =  "images/navi/"+theImgName+"_pas.gif";
	}
}

function makeNavActive() {
	//navi aktivieren, wenn die href des aktuellen navi-punkts der window.location.href entspricht
	windowHref = cleanHref();	
	
	var links = document.getElementsByTagName('a');
    
    for(var i = 0; tag = links[i]; ++i) {
   	    if(tag.className == 'navilink') {
   	    	if(links[i].href == windowHref) {
   	    		links[i].firstChild.src = "images/navi/"+extractFilename()+"_act.gif";
   	    	}
   	    }
    }
}