$consulta1=mysql_query("SELECT DISTINCT marca from jos_Sector");
   echo "Filtrar por sector:";
   echo "<br>";
   echo "<select name='sector' id='sector' onchange='submit()' style=\"width:235px\" ";
   echo "><option value='0'>Seleccione sector</option>";
      while($registro=mysql_fetch_row($consulta1))
   {
         echo "<option value='" .$registro[0]."'>$registro[0]</option>";
   }
echo "</select>";
   //echo "<input id=\"button\" type=\"button\" onclick=\"submit()\" value=\"OK\" />";
   echo "<br>";
   echo "<br>";

function creaquery($campo, $user = $_SESSION['userlogin'])
{
	if(!empty($campo))
	{
		 $querido="NOMBREDEL CAMPO = ".$campo;
		 $query = mysql_query("UPDATE db_game SET $querido WHERE user='$user'");
 
                 if($query)
                 {
                    return TRUE;
                 }
        }
 
           return FALSE;
}

<?php
$ua = get_browser('Mozilla/5.0 (X11; U; Linux i686; es-MX; rv:1.9.2.13) Gecko/20101206 Ubuntu/10.04 (lucid) Firefox/3.6.13', true);
print_r($ua);
?>

<?php
$ua = get_browser('Mozilla/5.0 (X11; U; Linux i686; es-MX; rv:1.9.2.13) Gecko/20101206 Ubuntu/10.04 (lucid) Firefox/3.6.13', true);
print_r($ua);
?>
 

<?php
if(empty($_SERVER['HTTP_USER_AGENT']))
{
   echo "No existe user agent";
   exit;
}
$nav = get_browser();
print_r($nav);
?>