function showtab(tabname) {
    if (tabname == "divOtel") {
        document.getElementById("divOtel").style.visibility = "visible";
        document.getElementById("divTur").style.visibility = "hidden";
        document.getElementById("divGemi").style.visibility = "hidden";
    }
    if (tabname == "divTur") {
        document.getElementById("divOtel").style.visibility = "hidden";
        document.getElementById("divTur").style.visibility = "visible";
        document.getElementById("divGemi").style.visibility = "hidden";
    }
    if (tabname == "divGemi") {
        document.getElementById("divOtel").style.visibility = "hidden";
        document.getElementById("divTur").style.visibility = "hidden";
        document.getElementById("divGemi").style.visibility = "visible";
    }
}
//