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Invalid HTML considered harmful
Posted by Bob Jonkman on April 28th, 2009
Valid HTML is not just useful for browsers. One of the big benefits of having valid HTML is that search engines can properly index your site. If the HTML is invalid, then the search engines may index you incorrectly, or not at all. Google isn’t the only search engine out there, and you want to drive as much traffic to your site as possible.
There appears to be some contention whether valid HTML makes a difference to search engines or not. Some say it doesn’t; or that it depends on the search engine; others have evidence it matters a lot.
Even if you’re not coding by hand, I urge you to have a look at HTML Dog, a set of tutorials on creating valid HTML. When things don’t work as expected you can turn here for examples in XHTML.
If you’re going to be using an editor for your Web pages, pick an editor that creates proper HTML code. Abandon FrontPage. I suggest using KompoZer, which is based on the same rendering engine as Firefox (Gecko).
You should also be checking your pages in Opera, which is a browser that is even better for standards-compliance than FireFox. The Chief Technology Officer for Opera is the same guy that wrote the Cascading Style Sheets specification, so it has a good pedigree.
If you’re using Firefox then be sure to check your pages with the HTML Validator addon:
http://users.skynet.be/mgueury/mozilla/
And when you think your site is done, check each page with the full-strength validator:
http://validator.w3.org/http://jigsaw.w3.org/css-validator/
<heavy sigh… />
–Bob.
March 20th, 2010 at 9:54 pm
Ironically, this page does not validate.
March 20th, 2010 at 10:34 pm
I know it. And I’m not happy about it.
This is a WordPress blog, which is oodles better than the Blogspot blog I used to use. But, as you point out it’s not perfect either.
I’m not sure if the invalid HTML comes as a result of the templates or themes I’m using, or if the WordPress code itself is sloppy. Certainly the editor is terrible. I compose the posts with the non-WYSIWYG editor, but it won’t let me insert certain types of markup. For example, I tried to put in a URL with the tel: URI scheme, but the editor won’t accept that. <a href=”tel:+1-519-635-9413″> has the “tel:” stripped out. Listen, WordPress, I’m editing the code, and you should do what I tell you to.
Sigh. Thanx for your sympathies.
–Bob.
March 21st, 2010 at 12:52 pm
The bug is probably mostly in your theme. I run WordPress at my site, and generate fully well-formed XHTML as well as mostly-valid XHTML5 (I output some legacy meta tags that HTML5 hates, I also use the rev=”" attribute which I do not believe should have been removed, and my use of ins and del tags is often just day-level granularity on datetime=”")
Are you using the vanilla theme? I could probably help you fix it up
About the inserting tel: links : do you have the WYSIWYG editor off completely, or are you using the “code” tab on it? Turning it off is much safer.
I also use http://wordpress.org/extend/plugins/x-valid/ to make sure that commentors cannot insert markup that breaks my well-formedness.
August 15th, 2010 at 6:08 am
Thanks for the info. The topic This Blog Is Not For Reading » Blog Archive » Invalid HTML considered harmful was just what I was looking for. Will bookmark!
December 26th, 2010 at 1:53 pm
[...] the page up high. That counts for all search engines, not just Google. I’ve written about this in Invalid HTML Considered Harmful. There are consultants that can help you correct invalid HTML; you may know one or two [...]