The behaviour of these functions is affected by settings in php.ini.
| Name | Default | Changeable | Changelog | 
|---|---|---|---|
| tidy.default_config | "" | PHP_INI_SYSTEM | |
| tidy.clean_output | "0" | PHP_INI_USER | PHP_INI_PERDIR prior to PHP 5.4.0 | 
Here's a short explanation of the configuration directives.