What about the valid html of a site to be crawled for search engines ?..
I mean... its vital to the site to be i.e. 100% XHTML Compliant with no errors ?.. or at few errors, the site or web page, goes down ?..

cheers!!..

Originally Posted by javigui

What about the valid html of a site to be crawled for search engines ?..
I mean... its vital to the site to be i.e. 100% XHTML Compliant with no errors ?.. or at few errors, the site or web page, goes down ?..

cheers!!..

As long as the errors you've made are not so bad that it stops the crawler from reading your page, I can'r see there being a problem. You only have to check a few top ranking sites to see that your pages don't need to validate.

Being XHTML (as compared to e.g. HTML 4.0.1) isn't very important. Serving valid HTML in genereal... It can perhaps matter a little if you have many errors in important areas. (i.e. if your HTML tags are completely off and wrong)

There is a thread on the effects of valid code on SEO

It has no effect.

having a validated site probably will do nothing for you but bragging rights.

it's kind of a thing amongst designers. especially css coders

Correct Matt -- it's a "thing" among Professional Webmasters who've been doing sites for many years, as we take great pride in having sites that are 100% code-compliant ... beyond that, valid code, no matter what the format, has nothing to do with being "crawled for search engines".

thanks for sharring that link with us - yea, just think about it, how DOES it realy have an effect?? and why should it have? no effect thats the answer. . .

Many things... Mainly, a simply unknown tag like "ALT" into an embedded flash, produces a validation error... A link to RSS feed, after meta tags, another error...
I'm just looking for another opinions, related to recently a migrate a complete site to XHTML, and I saw some changes at search engines...

PD: if I were looking for post a link, I would prefer o dozens of sites before this: 1) This is a site related to discuss webmaster related issues.
2) I would look for other pages, with a higher PR and without registration.

Originally Posted by roy77

thanks for sharring that link with us - yea, just think about it, how DOES it realy have an effect?? and why should it have? no effect thats the answer. . .

I don't think Google gives a rat's behind whether your markup is xhtml strict or spaghetti. The main thing about good code is that you have less worry that a browser on a system you're not running is going to guess differently than you intended, and show your page wrong.

I'm shocked how many people view my site on OS/2.

valid html will help bots to read your page .

Originally Posted by trichnosis

valid html will help bots to read your page .

Do you have an example of a non-valid page that wasn't read by a bot? Cos I ain't seen any.

Bots have no problem reading non-valid pages. The evidence is right on your doorstep, all you have to do is check the top ranking pages for a few searches.

There has been a lot of discussion about the importance of valid HTML, XHTML, etc. lately. Here is what you need to know:

1) By definition 'Valid HTML' means that the coding meets all W3C standards (http://validator.w3.org/). There is a distinct difference between Valid HTML and working HTML. It is important to understand the difference.

2) Working HTML means that a text browser (http://lynx.isc.org/) can render a web page from start to finish. Internet Explorer and Firefox are not text browsers. They are graphical browsers.

3) Different versions of HTML markup use different variations of certain codes or exclude certain tags or attributes. Search engines do not care if you mix and match as long as your HTML will work properly in a text browser. For example, Google does not differentiate between <br> and <br />.

4) Graphical browsers like Firefox and Internet Explorer will 'fix' or render properly some errors that will have a major impact on a text browser or search spider. For example, an improperly coded A HREF tag may render fine in a graphical browser but in a text browser the same code could extend the offending link all the way to the bottom of the document and include in that offending link's anchor text all the document text that follows, including any additional links that were supposed to have occurred.

5) You cannot always tell from a search engine's cache when crawl errors occur. Search engine caches pretty much regurgitate HTML markup so if the original looks good in a graphical browser chances are the cache will look good too, even when there really is an underlying error.

6) While it is not necessary to W3C validate your markup (HTML code) it is a good idea to do so. It ensures clean markup and that the search engines will succeed in their work. Like good programmers use REM (Remark) statements to document their code and keep track of their work, validation is not required, it's just smart.

Think of the guy at Boeing who installs the same screws into every airplane and has installed those same screws into 300 jets. He still logs every screw he installs. Logging those screws doesn't make the plane fly better. But it does help to keep track of things and to avoid costly future errors. Likewise, validation is a good habit to get into.

Originally Posted by trichnosis

valid html will help bots to read your page .

It wouldn't effect bots. They don't render a page like a browser does, They look at a page like we would look at a page in a text editor.

When it comes to bots, spiders, algos, and everything else that makes a search engine and SERPS presentation, the danger of bad markup is not in the reading, it is in the interpretation.

I like the A HREF example because it is an error I have seen personally. Awhile back I was working on a website that ranked fine in Google but was nowhere to be seen in Yahoo!, MSN or ASK. Upon opening the page in a text browser--a page which rendered perfectly in FF & IE--I saw that two-thirds of every page was one big link. Using the W3C validation tool I found the error (it was in an include used on practically every page of the website) and fixed it. Within a month the website was getting top rankings in Yahoo! and MSN. It is apparent that Yahoo! and MSN were unable to reconcile the error on the fly and hence it affected the rankings.

To reword what I said earlier, the benefit of validation to SEO, and web design in general, is to make certain you markup is debugged and that there is nothing that can trip-up the search engines. It's a better safe than sorry methodology.

Ask not how little you can do for your website but what you can do to make your website as slick as a well greased pig.