PHP UTF-8 mb_convert_encode and Internet-Explorer - php

Question

Since some days I read about Character-Encoding, I want to make all my Pages with UTF-8 for Compability. But I get stuck when I try to convert User-Input to UTF-8, this works on all Browsers, expect Internet-Explorer (like always).
I don't know whats wrong with my code, it seems fine to me.
I set the header with char encoding
I saved the file in UTF-8 (No BOM)
This happens only, if you try to access to the page via $_GET on the internet-Explorer myscript.php?c=äüöß
When I write down specialchars on my site, they would displayed correct.
This is my Code:
// User Input
$_GET['c'] = "äüöß"; // Access URL ?c=äüöß
//--------
header("Content-Type: text/html; charset=utf-8");
mb_internal_encoding('UTF-8');
$_GET = userToUtf8($_GET);
function userToUtf8($string) {
if(is_array($string)) {
$tmp = array();
foreach($string as $key => $value) {
$tmp[$key] = userToUtf8($value);
}
return $tmp;
}
return userDataUtf8($string);
}
function userDataUtf8($string) {
print("1: " . mb_detect_encoding($string) . "<br>"); // Shows: 1: UTF-8
$string = mb_convert_encoding($string, 'UTF-8', mb_detect_encoding($string)); // Convert non UTF-8 String to UTF-8
print("2: " . mb_detect_encoding($string) . "<br>"); // Shows: 2: ASCII
$string = preg_replace('/[\xF0-\xF7].../s', '', $string);
print("3: " . mb_detect_encoding($string) . "<br>"); // Shows: 3: ASCII
return $string;
}
echo $_GET['c']; // Shows nothing
echo mb_detect_encoding($_GET['c']); // ASCII
echo "äöü+#"; // Shows "äöü+#"
The most confusing Part is, that it shows me, that's converted from UTF-8 to ASCII... Can someone tell me why it doesn't show me the specialchars correctly, whats wrong here? Or is this a Bug on the Internet-Explorer?
Edit:
If I disable converting it says, it's all UTF-8 but the Characters won't show to me either... They are displayed like "????"....
Note: This happens ONLY in the Internet-Explorer!

Answer 1

Although I prefer using urlencoded strings in address bar but for your case you can try to encode $_GET['c'] to utf8. Eg.
$_GET['c'] = utf8_encode($_GET['c']);

Answer 2

An approach to display the characters using IE 11.0.18 which worked:
Retrieve the Unicode of your character : example for 'ü' = 'U+00FC'
According to this post, convert it to utf8 entity
Decode it using utf8_decode before dumping
The line of code illustrating the example with the 'ü' character is :
var_dump(utf8_decode(html_entity_decode(preg_replace("/U\+([0-9A-F]{4})/", "&#x\\1;", 'U+00FC'), ENT_NOQUOTES, 'UTF-8')));
To summarize: For displaying purposes, go from Unicode to UTF8 then decode it before displaying it.
Other resources:
a post to retrieve characters' unicode