DirtyMarkup combines the power of HTML Tidy, CSS Tidy, JS Beautify, and the Ace editor to effortlessly clean up your messy code. Just paste your code into the editor and press "clean". Now supports HTML5!
JTidy is a Java port of HTML Tidy, a HTML syntax checker and pretty printer. Like its non-Java cousin, JTidy can be used as a tool for cleaning up malformed and faulty HTML. In addition, JTidy provides a DOM interface to the document that is being processed, which effectively makes you able to use JTidy as a DOM parser for real-world HTML.