Does any free HTML repair tool exist? The one which not only shows but can also automatically repair HTML errors? Like this one: http://www.netmechanic.com/products/HTML_Toolbox_FreeSample.shtml which is not free though.
http://validator.w3.org/ It will tell you errors. So you can fix it. Use W3C compliant html editor like kompozer. .
I have tried Tidy today. I cleaned the code of my main page, copied it from Tidy and pasted it in the index.php of my theme. It worked well this far. But then the problem arose: how to paste the clean code in single.php for each single post? I tried pasting the clean code for one post from Tidy in to single.php in the theme editor and the subsequent result was that no matter which post I clicked on the main page of my blog, it would open only the post whose clean code I had pasted in single.php. Since that was not workable, I had to paste back the original, untidy code in single.php in the theme editor. Any idea where to paste in the theme editor the code that has been cleaned by Tidy for single posts?
I don't know. I kind of like learning HTML first instead of thinking there must be some software to fix my mistakes. But as long as we're on the subject, I keep making mistakes with my calculator. Does someone have some software that will automatically correct my mistakes? Oh, and it has to be free.