HTMLPurifier允许居中文本

$config = HTMLPurifier_Config::createDefault();
$config->set(\'CSS.AllowedProperties\', \'text-align\');
$purifier = new HTMLPurifier($config);

AttrDef

text-align

$css = $purifier->getCSSDefinition();
$css->info[\'text-align\'] = new HTMLPurifier_AttrDef_Enum(array(\'center\'));

// should allow text-align:center but not text-align:right or the likes:
$purifier->purify(/* ... */);