function ShowModalDialog(url, title, width, height) 
{
    if(width == null)
        width = 600;
    if(height == null)
        height = 600;

    var pWin;
    
    if (window.showModalDialog) 
    {
        pWin = window.showModalDialog(url, title, "dialogWidth:" + width + "px;dialogHeight:" + height + "px");
    }
    else 
    {
        pWin = wwindow.open(url, title, 'height=' + height + ',width=' + width + ',toolbar=no,directories=no,status=no, menubar=no,scrollbars=no,resizable=no,modal=yes');
    }        
}