php中英文字符串转字母转大小写

<?php //转小写 function lowercase($a){ $b = str_split($a, 1); $r = ''; foreach($b as $v){ $v = ord($v); if($v >= 65 && $v<= 90){ $v += 32; } $r .= chr($v); } return $r; } //转大写 function capital($a){ $b = str_split($a, 1); $r = ''; foreach($b as $v){ $v = ord($v); if($v >= 97 && $v<= 122){ $v -= 32; } $r .= chr($v); } return $r; } ?>