function popup(page,name,w,h,offset,features)
{
    var settings = 'height=' + h + ',';
        settings += 'width=' + w + ',';
        settings += 'top=' + offset + ',';
        settings += 'left=' + offset + ',';
        settings += features;

    win = window.open(page,name,settings);
    win.window.focus();
}

function offsetPopup(page,name,w,h,offset,features)
{
    if (screen.width) {
        x = (w + offset < screen.width) ? offset : 0;
        y = (h + offset < screen.height) ? offset : 0;
    } else {
        x = 0;
        y = 0;
    }
    if (x < 0) x = 0;
    if (y < 0) y = 0;

    var settings = 'height=' + h + ',';
        settings += 'width=' + w + ',';
        settings += 'top=' + y + ',';
        settings += 'left=' + x + ',';
        settings += features;

    win = window.open(page,name,settings);
    win.window.focus();
}

function centeredPopup(page,name,w,h,features)
{
    if (screen.width) {
        var winl = (screen.width-w)/2;
        var wint = (screen.height-h)/2;
    } else {
        winl = 0;
        wint = 0;
    }
    if (winl < 0) winl = 0;
    if (wint < 0) wint = 0;

    var settings = 'height=' + h + ',';
        settings += 'width=' + w + ',';
        settings += 'top=' + wint + ',';
        settings += 'left=' + winl + ',';
        settings += features;
    win = window.open(page,name,settings);
    win.window.focus();
}