Reviews of Free Online HTML Code Validators
Why you should check your code with a HTML Validator?
If you don't check your HTML code it can cause some browsers to crash or not display your web page properly and most importantly, search engine spiders may not be able to pick up the text off your page with broken HTML. The same goes for broken links on your website. Most search engine quidelines recommend that the HTML code validates and Google is also using quality of content as a factor in it's Panda algorithm and that includes clean code.
To complicate the problem most blogs, CMS or WYSIWYG programs that allow you to design a website with no knowledge of HTML often produce HTML code that is outdated and therefore doesn't validate and they often have enormous code bloat besides. Even the newest versions are often not code compliant with the W3C, which regulates HTML code.
Code that links to your social networks may not validate. When that happens sometimes it helps to update the Doctype to HTML5.
If your website ranking has dropped then it might help to check your code with an HTML validator. If your website comes back in a few weeks then that was the problem. If not look for other problems such as Website Hijacking or look to see if there are any Technology Blockers in your code. If neither of those solve your problem then you might check out my Website SEO Analysis page as I may be able to figure out what is causing your ranking to drop.
Reviews of HTML Code Validators and Error Checkers
The following reviews cover sites offering a free online HTML Code Validator. Not all of them provide the same service and some are more thorough than others. If a site is having severe problems I prefer to use the W3C validator first and then try other programs which catch broken tags or links that W3C can miss. Be aware that if you have upgraded your site to HTML5 that not all validators have been upgraded to that version of HTML. Downloadable HTML validators are not included below although there is a add-on for Firefox you might try.
W3C HTML Validator
The W3C HTML Validator Service checks HTML documents for conformance to W3C HTML and XHTML recommendations and other HTML standards. This one is not as user friendly for beginners as the others, however, it is the one more experienced web designers should use. You should have a doc type declaration and also character type in the meta tags before it will analyze the HTML code correctly.
The W3C HTML validator gives an explanation for each error it finds and also has validators for other markup codes like CSS, RSS feeds and can also find broken links.
Dr. Watson HTML Validator
Dr. Watson also gives you several options for code analysis. Their search engine compatibility test checks your meta tags for the best use of keywords. Dr. Watson provides links to the HTML errors in your code which is very nice.
In spite of the non-spelling errors this is a good tool for an overall look at the quality of your website and to prevent problems with Google's Panda Algorithm which penalizes sites for poor quality content.
The Online Web Check Validator is a good one to use if you want a 2nd opinion as they provide useful information about the errors or warnings it finds and also which line the errors are on. It also provides information about the HTTP header, such as server type, type of content and if the page has been redirected or not.
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