HTML Tidy — Correct and tidy HTML code
HTML Tidy is a program for checking and tidying HTML files. It can tidy your code by doing automatic indentation, it can scan for errors and even generate a version of your code with the errors fixed. It can also be set up to always output code done to a specific standard, such as XHTML 1.0.
HTML Tidy is a highly useful tool for identifying your mistakes, cleaning up small errors and making your code readable.