Description
bool 
ctype_xdigit ( string text)
     Returns TRUE if every character in text is 
     a hexadecimal 'digit', that is a decimal digit or a character from 
     [A-Fa-f] , FALSE otherwise.
    
     
| 例子 1. A ctype_xdigit() example | 
<?php$strings = array('AB10BC99', 'AR1012', 'ab12bc99');
 foreach ($strings as $testcase) {
 if (ctype_xdigit($testcase)) {
 echo "The string $testcase consists of all hexadecimal digits.\n";
 } else {
 echo "The string $testcase does not consist of all hexadecimal digits.\n";
 }
 }
 ?>
 | 
 
       This example will output :
       | The string AB10BC99 consists of all hexadecimal digits.
The string AR1012 does not consist of all hexadecimal digits.
The string ab12bc99 consists of all hexadecimal digits. | 
 | 
    
     See also ctype_digit().