if ($_POST['Atribute1']) {
$atribute1 = $_POST['Atribute1'];
$atribute2 = $_POST['Atribute2'];
$both = $atribute1 . "+" . $atribute2;
header("Location: search.php?xSearch=$both");
exit();
}
You could chop it down by a few lines but the above should at least explain the process.
Also, why are you using a text link with javascript to submit your form? Just use a normal submit button and remove the javascript altogether.
<input name="submitbutton" type="submit" value="Submit" />