// check cookie., if not set - set, pop window, blur
//

function popUnder( id, url )
{
    if( getCookie( 'pop_' + id ) )
    {
        return;
    }

    setCookie( 'pop_'+id, '1', 20000, '/', '', '' );
        
    var win = window.open( url, 'offer', 'height=500,width=690,location=yes,menubar=yes,resizable=yes,scrollbars=yes,status=yes,toolbar=yes' );
    win.blur(); 
    window.focus();
}