function showtab1 () {
  if (document.getElementById)
    document.getElementById("tab1").style.display = "inline";
    document.getElementById("tab2").style.display = "none";
    document.getElementById("tab3").style.display = "none";

    document.getElementById("tabbody").className = "tabbody_pink";

    document.getElementById("navi1-left").className = "navi_pink_links tabinside";
    document.getElementById("navi2-left").className = "navi_grau_links tabinside";
    document.getElementById("navi3-left").className = "navi_grau_links tabinside";

    document.getElementById("navi1").className = "navi_pink_rechts tabinside";
    document.getElementById("navi2").className = "navi_grau_rechts tabinside";
    document.getElementById("navi3").className = "navi_grau_rechts tabinside";

};

function showtab2 () {
  if (document.getElementById)
    document.getElementById("tab1").style.display = "none";
    document.getElementById("tab2").style.display = "inline";
    document.getElementById("tab3").style.display = "none";

    document.getElementById("tabbody").className = "tabbody_blau";

    document.getElementById("navi1-left").className = "navi_grau_links tabinside";
    document.getElementById("navi2-left").className = "navi_blau_links tabinside";
    document.getElementById("navi3-left").className = "navi_grau_links tabinside";

    document.getElementById("navi1").className = "navi_grau_rechts tabinside";
    document.getElementById("navi2").className = "navi_blau_rechts tabinside";
    document.getElementById("navi3").className = "navi_grau_rechts tabinside";

};

function showtab3 () {
  if (document.getElementById)
    document.getElementById("tab1").style.display = "none";
    document.getElementById("tab2").style.display = "none";
    document.getElementById("tab3").style.display = "inline";

    document.getElementById("tabbody").className = "tabbody_gruen";

    document.getElementById("navi1-left").className = "navi_grau_links tabinside";
    document.getElementById("navi2-left").className = "navi_grau_links tabinside";
    document.getElementById("navi3-left").className = "navi_gruen_links tabinside";

    document.getElementById("navi1").className = "navi_grau_rechts tabinside";
    document.getElementById("navi2").className = "navi_grau_rechts tabinside";
    document.getElementById("navi3").className = "navi_gruen_rechts tabinside";

};