function logo(onOff){
         if (onOff==0) document.getElementById('logoEgo').src = 'img/egoLogo.gif';
         if (onOff==1) document.getElementById('logoEgo').src = 'img/egoLogo2.gif';
    }
    function tilia(onOff){
        // if (onOff==0) document.getElementById('tiliaTree').src = 'img/tiliaTreebw.gif';
         // if (onOff==1) document.getElementById('tiliaTree').src = 'img/tiliaTree.gif';
    }