Basic Binary Encoder/Decoder

<?php
if($_GET['Action'] == 'Encode'){
$array = str_split($_GET['Text']);
$result = '';
foreach($array as $item){
    $bin = decbin(ord($item));
    $bin = str_pad($bin, 8, "0", STR_PAD_LEFT);
    $result .= $bin;
}
echo $result;
} elseif($_GET['Action'] == 'Decode'){
    $array = str_replace(' ','',$_GET['Text']);
    if(strlen($array) % 8 !== 0){
        header('Location: Binary.php?Error=1');
        exit;
    } else {
        if(substr_count($_GET['Text'],' ') !== 0){
            header('Location: /Binary.php?Text='.urlencode(str_replace(' ','',$_GET['Text'])).'&Action=Decode');
            exit;
        }
    $array = str_split($array,8);
    $bin = '';
    foreach($array as $item){
    $result .= chr(bindec($item));
    }
    echo $result;
    }
} elseif(isset($_GET['Text']) && strlen($_GET['Text']) !== 0) {
    $value = str_replace(' ','',$_GET['Text']);
    if(is_numeric($value) && substr_count($value,1)+substr_count($value,0) === strlen($value) && strlen($value) %8 === 0){
        header('Location: /Binary.php?Text='.urlencode($value).'&Action=Decode');
        exit;
    } else {
        header('Location: /Binary.php?Text='.urlencode($_GET['Text']).'&Action=Encode');
        exit;
    }
} else {
?>

<form action="" method="get">
<input type="text" name="Text"><br>
<input type="radio" name="Action" value="Encode">Encode<br>
<input type="radio" name="Action" value="Decode">Decode<br>
<input type="submit" value="Submit">
</form>

<?php
}