ctype_lower
    (PHP 4 >= 4.0.4, PHP 5)
ctype_lower -- Check for lowercase character(s)
Description
bool 
ctype_lower ( string text)
     Returns TRUE if every character in text is 
     a lowercase letter in the current locale.
    
     
Example 1. A ctype_lower() example (using the default locale) 
<?php $strings = array('aac123', 'qiutoas', 'QASsdks'); foreach ($strings as $testcase) {     if (ctype_lower($testcase)) {         echo "The string $testcase consists of all lowercase letters.\n";     } else {         echo "The string $testcase does not consist of all lowercase letters.\n";     } } ?>
 |  
 
       This example will output :
       The string aac123 does not consist of all lowercase letters.
The string qiutoas consists of all lowercase letters.
The string QASsdks does not consist of all lowercase letters.  |  
  | 
    
     See also ctype_alpha(), ctype_upper(),
     and setlocale().