Broken code means that the page may not display correctly or function correctly in some browsers.
Someone using that obscure browser where the invalid code breaks the site goes elsewhere looking for the same information you have on a site that isn’t broken for them. They eventually find what they are looking for on a site that works and link to it from their related site.
The site they found gets the SEO boost from the relevant incoming link from their site instead of your site getting it.
As Felgall says, validation isn’t all that important purely from an SEO point of view. Google is trying to give people the sites that best match their queries, it isn’t trying to be the W3C’s policeman, so it won’t arbitrarily penalise sites for not validating.
That isn’t to say that validation isn’t important. Depending on what the errors are, sites that don’t validate can go horribly wrong in some or all browsers. And there’s no point in being #1 in the SERPs if people get to your site and find a garbled mess because their browser chokes on invalid code.
Well, one of my sites has like 600 errors but shows up fine on Chrome, firefox, and IE on both windows 7 and windows XP(don’t have a MAX or Linux to test on). I heard that valid code doesn’t show up right always on browsers.
Edit: Got it down to 180 or so errors now but most of them were changing “A” to “a” in “a href” which I don’t think any browser really cares about.
What about the thousands of other browsers. Have you tested your page in all of those as well?
If your page isn’t valid it is your fault if it doesn’t display correctly in any particular browser.
While not all browsers will display the page correctly if your page is valid, hundreds more browsers will display it correctly if it is valid than might display it correctly if it isn’t valid. So making sure it is valid improves your chances of getting it to display correctly in more browsers.
It isn’t as if the validation rules are all that difficult to meet if you actually learn HTML properly. It’s about the same order of difficulty as learning that it is valid to walk along the footpath but invalid to walk down the middle of the road. (Teaching computers to do either of those is far harder than teaching a person).
I don’t know exactly how many completely different browsers there are but I have seen lists that include well over 100 different browsers that will only run on Mac OSX and so given the relative popularity of different operating systems I would expect the overall total number of different browsers to be in the thousands. While most of those are used by just a handful of people, those people might be the ones who can do the most to promote your site and so while testing in all the different browsers isn’t practical you can at least improve your chances that your page will work in their browser by writing valid HTML instead of something that merely looks like HTML.
Actually just because something validates doesn’t mean it’ll work in all browsers, not even close. Google itself has dozens of errors.
Really, its pretty much impossible to make it display in every browser out there. Since 99% of the population uses maybe 4 or 5 browsers(if you count all the versions of IE as one), its smart just to focus on those.
Validation is actually pretty difficult, especially if you have adcode for advertising companies since most of those don’t validate.
No one has ever claimed that it does. All that has been said is that it is YOUR fault if it doesn’t display correctly because of invalid HTML/CSS. It is the browser’s fault if it doesn’t display correctly if your HTML/CSS is valid.
By using valid HTML and CSS you improve the chances of your page working in more browsers. There isn’t enough time to test in all browsers since there are several new browser versions released every day so all you can do to maximise your chances of the code working in as many browsers as possible is to write valid HTML/CSS and then test it in the most popular 5-10 browsers (including whatever old browser versions you consider to be still popular enough to want to make sure that it works there).
If your HTML/CSS DOESN’T validate then you increase the number of browsers that it will not work in - perhaps instead of there being 50 browsers it doesn’t work in there might be 500 different browsers it doesn’t work in. B y not using valid HTML you have stopped your site working for anyone using those 450 different browsers. While the total number of people actually using those obscure browsers may be small they may all be particularly interested in your topic and have their own web sites on related topics that they might have linked to yours if your site worked for them when they tried to visit.
Validation error can be for various reasons like attribute missing, sometime some tags are not close, some extra code which is not use etc. So, the rectification of those extra code or error means the processing time for the site will be high ( may be minor but good) and to be whenever we are doing something its should be proper.
But assume if you using some 3rd party CMS like Wordpress Joomla etc you cant able to fix those as some errors are for the JS validation etc.
So its true that in direct sense it will not effect in seo but it will help in processing time or the loading time of the site.