function bbcode($text = '')
{
    //конвертация кодов в теги регулярными выражениями
    // ББ коды
    $bbcode = array(
  '/\[url\](.+)\[\/url\]/isU' => '<a href="$1">$1</a>',
  '/\[url=(.+)\](.+)\[\/url\]/isU' => '<a href="$1">$2</a>',
  '/\[i\](.+)\[\/i\]/isU' => '<em>$1</em>',
  '/\[b\](.+)\[\/b\]/isU' => '<strong>$1</strong>',
  '/\[u\](.+)\[\/u\]/isU' => '<span style="text-decoration:underline;">$1</span>',
  '/\[big\](.+)\[\/big\]/isU' => '<span style="font-size:large;">$1</span>',
  '/\[small\](.+)\[\/small\]/isU' => '<span style="font-size:small;">$1</span>',
  '/\[code\](.+)\[\/code\]/isU' => '<code>$1</code>',
  '/\[red\](.+)\[\/red\]/isU' => '<span style="color:#ff0000;">$1</span>',
  '/\[yellow\](.+)\[\/yellow\]/isU' => '<span style="color:#ffff22;">$1</span>',
  '/\[green\](.+)\[\/green\]/isU' => '<span style="color:#00bb00;">$1</span>',
  '/\[blue\](.+)\[\/blue\]/isU' => '<span style="color:#0000bb;">$1</span>',
  '/\[white\](.+)\[\/white\]/isU' => '<span style="color:#ffffff;">$1</span>',
  '/\[color=(.+)\](.+)\[\/color\]/isU' => '<span style="color:$1;">$2</span>',
  '/\[size=([0-9]+)\](.+)\[\/size\]/isU' => '<span style="font-size:$1px;">$2</span>',
  '/\[img\](.+)\[\/img\]/isU' => '<img src="$1" alt=""/>'
  );
    return preg_replace(array_keys($bbcode), array_values($bbcode), $text);
}