# E.19 TidyFilter The `TidyFilter` allows you to use the [PHP tidy extension](http://php.net/tidy) to clean up and repair HTML documents. Usage example: ``` <filterchain> <tidyfilter encoding="utf8"> <config name="indent" value="true" /> <config name="output-xhtml" value="true" /> </tidyfilter> </filterchain> ``` Table E.15:聽 Attributes for the `<tidyfilter>` tag NameTypeDescriptionDefaultRequired`encoding``String`The expected input encoding of the file.utf8No E.19.1 Nested tags The `TidyFilter` supports nested <config> tags to configure how Tidy should manipulate the documents. For a complete list of configuration options see the official [Quick Reference](http://tidy.sourceforge.net/docs/quickref.html).