function tabs(number)  
    {
    document.getElementById("pnl1").style.display = 'none';                                                                              
    document.getElementById("pnl2").style.display = 'none';
    document.getElementById("pnl3").style.display = 'none';
    document.getElementById("pnl4").style.display = 'none';
    document.getElementById("pnl5").style.display = 'none'; 
    document.getElementById("pnl"+number).style.display = 'block';

    if (document.getElementById("bck1").className != 'hidetab') {
        document.getElementById("bck1").className = 'viewtab';
    }
    if (document.getElementById("bck2").className != 'hidetab') {
        document.getElementById("bck2").className = 'viewtab';
    }
    if (document.getElementById("bck3").className != 'hidetab') {
        document.getElementById("bck3").className = 'viewtab';
    }
    if (document.getElementById("bck4").className != 'hidetab') {
        document.getElementById("bck4").className = 'viewtab';
    }
    if (document.getElementById("bck5").className != 'hidetab') {
        document.getElementById("bck5").className = 'viewtab';
    }
    document.getElementById("bck" + number).className = 'selecttab';     
    }