function showproduct(PID) {
    if (document.all)
        var xMax = screen.width, yMax = screen.height;
    else
        if (document.layers)
            var xMax = window.outerWidth, yMax = window.outerHeight;
        else
            var xMax = 640, yMax=480;
    var xOffset = (xMax - 620)/2, yOffset = (yMax - 800)/2;
    window.open('model.php?i=' + PID, 'pic','width=620,height=800,screenX='+xOffset+',screenY='+yOffset+',top='+yOffset+',left='+xOffset+',copyhistory=no,directories=no, menubar=no,location=no,scrollbars=no,resizable=no');
}