function tabChange(tabNo) {
    var i;
    var tabCount = 2;
    
    for (i = 1; i <= tabCount; i++) {
        document.getElementById("tabsel" + i).className = "tab_selector";
        document.getElementById("tab" + i).className = "noshow";
    }
    
    document.getElementById("tab" + tabNo).className="tab";
}