It's a good idea to make sure your pages have proper HTML markup and you don't have broken links. It's easy to make mistakes in your pages with code and links, thus it's always a safe bet to run your site or pages through a validator before uploading to your site. What do HTML validation services do? They check the HTML code to make sure it follows certain standards. Much of the code for a gpEasy installation is generated by gpEasy CMS and the theme however, you can still cause some coding problems when you edit code in the source view of the HTML editor, CKEditor. Furthermore, it's good to double check gpEasy once in a while. . . believe it or not even the gpEasy developer(s) make mistakes from time to time and they need a little help spotting these things.
There are several validation services on the net but I mainly use three.
The w3c has a markup validation service that allows you to validate by several methods, URL, upload file, or direct input. You can find it here. Since the w3c is the HTML standards body it's a good idea to check against them every so often. They also have a link checker here. They have several other validation services but those are the main two I suggest you check your site against.
Another service I suggest is WDG (Wed Design Group). You can find their tools here. Their HTML validator will validate 100 pages of your site and they have a link checker as well.
Finally, there's Total Validator. Again, this service has several options and modes. Also, it can be downloaded as an add-on for Firefox; however, the Total Validator add-on didn't work properly with my site so I bagged it and went with the HTML Validator and Validity add-ons for Firefox. There are also Google Chrome HTML validation extensions; Validity, HTML Validator, and XHTML Validator. While there are other add-ons and extension available I've had the best luck with the ones I've linked.
To check links on my local installation I use Xenu's Link Sleuth. It's a nice little portable program that will run through your site or local installation and check links to see if they are broken. It's very handy. Combined with and extension or add-on and you can check your local installation of gpEasy for validity before uploading to your server.
One word of caution on checking your local installation is, when you are logged in sometimes you might get strange errors thus it's good to log out and do a thorough check to make certain that errors are not due to Admin pages.
While this really isn't a tutorial it's still a good idea to become familiar with validating your pages for both links and HTML code. That's it for this one, head over to the gpEasy tutorials for more.