function wechsel0()

    {
document.styleSheets[0].disabled=false;
document.styleSheets[1].disabled=true;
document.styleSheets[2].disabled=true;
    }

function wechsel1()

    {
document.styleSheets[0].disabled=true;
document.styleSheets[1].disabled=false;
document.styleSheets[2].disabled=true;
    }

function wechsel2()

    {
document.styleSheets[0].disabled=true;
document.styleSheets[1].disabled=true;
document.styleSheets[2].disabled=false;
    }