Us web developers are a proud people that want to build the best websites every single time. To help us identify areas that could be improved, I’ve compiled a list of various automated and manual checks that can help us make better websites. My professional pride urges me to do the entire list, but I must admit that I sometimes skip some of the checks due to time constraints. I did just finish a project where I did all the checks and that felt very satisfying.


Mark-up validation

Choose the right DOCTYPE and make sure that the mark-up you write conforms to that DOCTYPE. No matter if you choose HTML or XHTML, always go for a strict DOCTYPE since it forces all browsers to render in standards compliant mode. Otherwise, you might end up with different renderings. Here is a list of DOCTYPEs to choose from. Remember that real men use XHTML 1.0 Strict or XHTML 1.1.

I use the Total Validator or the W3C validator to validate the mark-up against the DOCTYPE.

Stylesheet validation

It’s always a good idea to validate your stylesheets against the W3C standards. You will probably find a lot of small things you can easily fix. This is also to ensure better browser compatibility, but it is not as important as mark-up validation. In some cases you deliberately put hacks in your stylesheets to cope with browser differences and that might break the validation. The W3C CSS validator works for me.

RSS and ATOM feed validation

There are literally hundreds of feed aggregators on the market today and that doesn’t include the custom aggregation done by blog engines, content management systems etc. To ensure they can all read your RSS and ATOM feeds, make sure to validate them against the standard.

Accessibility validation

Make sure your mark-up is structured in a way that is readable for everyone. There are two standards widely used today and that’s the Section 508 used in America and the WAI which is more comprehensive. It is pretty easy to make your site compliant with the rules of Section 508, so you should as a minimum do that.

The WAI is split up into three categories: A, AA and AAA where A is the simplest and AAA is the most comprehensive. If you can make your site validate Section 508, you should easily be able to validate against WAI-A. In Europe all government websites must conform to WAI-AA. If you are hardcore and stubborn, you should go for the WAI-AAA valid website. For a regular website, this is not easy but it can be done.

You can perform the validation using the Total Validator or Cynthia Says.



Before finishing your website, make sure to check the YSlow grade. It has to be as high as possible. Also make sure to use Fiddler to analyze the request/response graph by Internet Explorer. Using those two tools can make your site twice as fast with just minor tweaks.

Use general website analysis

It is a little redundant using the Website Analyzer after you’ve optimized the page using YSlow and Fiddler, but it almost always give you inspiration on where to do further performance optimizations.

No errors

Broken links check

This one requires no explanation. Take an automated test for broken links before releasing.

Browser compatability

Even though you have produced valid mark-up and CSS, there is always a need to go through all the pages of the website to make sure they look good in Internet Explorer 6, Firefox 2, Opera 9, Safari 2.5, Chrome and newer versions hereof. The number of different browsers you need to check varies by the type of website and the target group. This check is unfortunately manual and can take a loooong time.

Add meaning to content


You don’t need to know an awful lot about search engine optimization to do just the basic stuff right. I suggest you at least install the senSEO add-on to Firefox. It will provide you with a lot of useful tips and tricks by analyzing your mark-up and suggest improvements

Semantic Extractor

The Semantic Extractor can help you find inconsistencies in the structure of the different tags on your website. It lets you see how the search engine crawlers understand your site.

P3P Policy

If you set cookies then you need to have a P3P policy HTTP header as a minimum. The header briefly describes how the website behaves in regards to privacy. You might also want to add a more complete privacy statement in a certain XML format. The benefit is that your website will receive elevated privileges under stricter security settings in Internet Explorer. Learn more about P3P. Remember also to validate your P3P policy.


The PICS-label is also an HTTP header, but it describes the type of content on your website. The PICS-label is used by various tools build to protect kids on the web, such as NetNanny etc. Learn more about PICS.

Use semantic mark-up where it makes sense

Are you listing events or contact information then wrap them in meaningful mark-up such as microformats. This adds extra meaning to your content and opens the door to data portability. Here is an introduction to semantic mark-up.

Go mobile

This is relevant if you’re website is targeted mobile clients such as PDA’s and smartphones.

MobileOK Checker

Run your website through this online tool that will give you a lot of good feedback on your code. The W3C made it to provide a set of best-practices for mobile web apps.


This DOCTYPE can be difficult to code against if your website is targeted both mobile and richer browsers. However, if you are creating a mobile-only website then this DOCTYPE is for you. It’s basically a stripped down version of the XHTML 1.1 DOCTYPE with some mobile specific enhancements.

Input mode

One of the enhancements of the XHTML Basic 1.1 DOCTYPE is the inputmode attribute on textarea and text input fields. It allows you to specify the type of input that is best suited for the input field. It could be digits, Latin lowercase letters or Greek letters. Devices that understand this attribute will then adjust the input mode.

Checklist for high quality websites part 2


Comments are closed