function sec1() {
    createStyleRule("#sec1", "display:none;");
    createStyleRule("sec2", "display:none;");
    createStyleRule("#sec3", "display:none;");
    document.getElementById('p1').className = 'on';
    document.getElementById('p2').className = 'off';
    document.getElementById('p3').className = 'off';
    return false;
}
function sec2() {
    createStyleRule("#sec1", "display:none;");
    createStyleRule("sec2", "display:none;");
    createStyleRule("#sec3", "display:none;");
    document.getElementById('p1').className = 'on';
    document.getElementById('p2').className = 'off';
    document.getElementById('p3').className = 'off';
    
}
function sec3() {
    createStyleRule("#sec1", "display:none;");
    createStyleRule("sec2", "display:none;");
    createStyleRule("#sec3", "display:none;");
    document.getElementById('p1').className = 'on';
    document.getElementById('p2').className = 'off';
    document.getElementById('p3').className = 'off';
    return false;
}