Validating markup after every post, page or plugin installation

It is always important to validate your XHTML markup everytime you make any change or update to your website. This helps you to maintain a well structured content and XHTML elements.

Just this morning, I installed wordpress’s wordpress events calendar plugin.  After installing it had 193 validation errors as shown in the image below despite that prior to that I had none except just a single warning.

Validation with calendar option selected in the widget

Validation errors can break the structure of your content and the relationship of your content items. Imagine, setting a font-size of 1.1em for the h1 header and you forget to close the header somewhere in your page. It means that visually your website would look normal but to other browsers or search engines it would appear as though, you have one huge chunk of your content marked up as header without any following content.

Moreover, to the search engines it would seem you are trying to spam them by over-emphasising the importance of your text by enclosing it in H1 heading.

So for more reasons why you should validate, why not check out the previous website reviews, University of Botswana, Trade and Industry and Communications websites.

If you are still not convinced, you can read Validating a website from wordpress codex or the HTML Validator’s take on why you should validate your site.