(PHP 4 >= 4.3.0, PHP 5, PHP 7)
mb_strtoupper — Make a string uppercase
$str
[, string $encoding = mb_internal_encoding()
] )
Returns str
with all alphabetic characters converted to uppercase.
strThe string being uppercased.
encodingThe encoding
parameter is the character encoding. If it is omitted, the internal character
encoding value will be used.
str with all alphabetic characters converted to uppercase.
For more information about the Unicode properties, please see » http://www.unicode.org/unicode/reports/tr21/.
By contrast to strtoupper(), 'alphabetic' is determined by the Unicode character properties. Thus the behaviour of this function is not affected by locale settings and it can convert any characters that have 'alphabetic' property, such as a-umlaut (ä).
Example #1 mb_strtoupper() example
<?php
$str = "Mary Had A Little Lamb and She LOVED It So";
$str = mb_strtoupper($str);
echo $str; // Prints MARY HAD A LITTLE LAMB AND SHE LOVED IT SO
?>
Example #2 mb_strtoupper() example with non-Latin UTF-8 text
<?php
$str = "Τάχιστη αλώπηξ βαφής ψημένη γη, δρασκελίζει υπέρ νωθρού κυνός";
$str = mb_strtoupper($str, 'UTF-8');
echo $str; // Prints ΤΆΧΙΣΤΗ ΑΛΏΠΗΞ ΒΑΦΉΣ ΨΗΜΈΝΗ ΓΗ, ΔΡΑΣΚΕΛΊΖΕΙ ΥΠΈΡ ΝΩΘΡΟΎ ΚΥΝΌΣ
?>
Please note, that in many cases, forcing UTF-8 encoding with second parameter is necessary. PHP documentation states that if this parameter is omitted, the internal character encoding value will be used. But in my case it turned out to be not true. Even though I have all my pages encoded in UTF-8 and my DB connection set to force UTF-8 encoding, comparison of user-input and DB-retrieved data, which is using mb_strtoupper, did not work until I forced encoding.
mb_strtoupper() will not convert the German "ß" character into its (relatively new) uppercase form ("ẞ").
mb_strtolower() will, however, convert the uppercase form into a lowercase "ß". (tested with PHP 5.5.0)
"SS" is still the most common uppercase presentation of "ß". If you want this, you'll have to do it manually:
<?php
mb_internal_encoding("UTF-8");
echo mb_strtoupper("Maß\n"); // "MAß"
echo mb_strtolower("MAẞ\n"); // "maß"
echo mb_strtoupper(str_replace("ß", "SS", "Maß\n")); // "MASS"
?>
for some reason, there are instances that special characters do show when you use this function, but when you revisit or refresh the page the special characters doesn't appear anymore, ie GRSARMERING is being displayed instead of GRÆSARMERING. You have to provide the second parameter which charset you are using to override the value. in my case it's iso-8859-1, so the function would now look like
mb_strtoupper($foo, 'iso-8859-1')
