var actualImage = new String("but3");
var oldImage = new String("but3");

var actual = new String("but3");
var old = new String("but3");

if (document.images) {

        var but1on = new Image();
        but1on.src = "img/company_a.gif";
        var but1off = new Image();
        but1off.src = "img/company.gif";

        var but2on = new Image();
        but2on.src = "img/kuenstler_a.gif";
        var but2off = new Image();
        but2off.src = "img/kuenstler.gif";

        var but3on = new Image();
        but3on.src = "img/produkte_a.gif";
        var but3off = new Image();
        but3off.src = "img/produkte.gif";
		
		var but4on = new Image();
        but4on.src = "img/kontakt_a.gif";
        var but4off = new Image();
        but4off.src = "img/kontakt.gif";
		
        var but5on = new Image();
        but5on.src = "img/aktuelles_a.gif";
        var but5off = new Image();
        but5off.src = "img/aktuelles.gif";
}


function img_act(imgName) {
        if (document.images) {
                if(imgName != actualImage) { 
                        imgOn = eval(imgName + "on.src");
                        document [imgName].src = imgOn;
                }
                else{
                        imgOn = eval(imgName + "on.src");
                        document [imgName].src = imgOn;
                }
        }
}

function img_inact(imgName) {
        if (document.images) {
                if(imgName != actualImage) {
                        imgOff = eval(imgName + "off.src");
                        document [imgName].src = imgOff;
                }
                else{
                        imgOff=eval(imgName + "off.src");
                        document[imgName].src = imgOn;
               }
        }
}

function img_set(imgName) {
        if(document.images) {
                oldImage = actualImage;
                actualImage = imgName;
                img_inact(oldImage);
                img_act(actualImage);
        }
}