JTidy refers to the Java port of popular HTML cleanout tool called HTML Tidy. HTML Tidy is an application that helps check invalid syntax in HTML.  With good syntax, HTML provides good-looking and functional web pages.  With its association to the Java port, JTidy is created with basically the same purpose of cleaning out invalid syntax or HTML codes.

The JTidy application or initiative was started out and maintained by Andy Quick.  Upon his step-down from the post, the codes for JTidy are now re-developed, enhanced, and maintained by various volunteers across the globe.  Despite this change-up though, JTidy remains to be a useful HTML checker and so-called pretty printer. HTML or Hypertext Markup Language is considered the standard markup language when it comes to the creation of web pages.  It is through HTML codes that the first web pages are born and launched for the world to see. In the eyes of the internet surfer or user, HTML may be more like a collection of text and images that are placed in certain layouts to give them a nice look and for functionality.  Behind the design and functionality of web pages though are HTML codes. Every part of the page is controlled or managed through the writing of tags, syntax, or codes.  With all codes manually written, the chances of errors are also high.  This is the part where JTidy comes in.  Under the Java platform, JTidy helps to check proper syntax in order for the page to be viewed properly. Syntax checking also helps the overall functionality of web pages.

Aside from cleaning up and checking syntax in HTML through the Java port, JTidy also performs other functions including the provision of a DOM interface. This function is done while a particular document is being used or processed.  This also explains why some people also refer to JTidy as a DOM parser.