<?php
  $ah = prepare_ansicode();

  mb_internal_encoding('UTF-8');

  $str = "<p>\xc2\xa0</p><p>我是測試字串</p>";
  $str2 = str_replace("\xC2\xA0", '', $str);
  $str3 = preg_replace("/\xC2\xA0/i", '', $str);
?>
  <div style="background-color: black; color: gray;">
  <?php
  manifest($str);
  manifest($str2);
  manifest($str3);
  ?>
  </div>

<?php
  function manifest($str) {

    $nl = '<br />';

    global $ah;

    echo "{$ah[33]}$str{$ah[0]}\n";
    $k = 0;
    for ($i = 0; $i < mb_strlen($str); ++$i) {
      $mbc = mb_substr($str, $i, 1);
      $mbcbytes = manifest_mb($mbc);
      $k += count($mbcbytes);
      $mbcexp = implode(' ', $mbcbytes);
      echo "{$ah[32]}$mbc{$ah[0]} ($mbcexp) ";
      if ($k > 7) {
        echo $nl;
        $k = 0;
      }
    }
    echo $nl . $nl;
  }

  function manifest_mb($mbc) {
    $ret = Array();;
    for ($i = 0; $i < strlen($mbc); ++$i) {
      $ret[] = sprintf('%x', ord($mbc[$i]));
    }
    return $ret;
  }

  function prepare_ansicode() {
    $colors = Array( 'black', 'red', 'green', 'yellow', 'blue', 'purple', 'cyan', 'white' );

    $ah = Array();
    for ($i = 30; $i <= 37; ++$i) {
      $ah[$i] = "<span style='color:{$colors[$i-30]};'>";
    }
    $ah[0] = '</span>';
    return $ah;
  }