function showDiv(obj) {
        hideDiv();
        document.getElementById(obj).style.visibility = "visible";
    }
            
function hideDiv() {
        document.getElementById("what").style.visibility = "hidden";
                document.getElementById("galerie").style.visibility = "hidden";

        
            }

function showDivLg(obj) {
        document.getElementById(obj).style.visibility = "visible";
    }
    

function hideDivLg() {

                  document.getElementById("galerie").style.visibility = "hidden";

        
            }