Google doesn't take into account W3C errors for SEO. There are so many big websites with a bunch of errors which have a good ranking in Google for many keywords.
Having a W3C compliant website is good practice because you're sure your website respect rules of web semantic but there is no influence for SEO unless you have invalid HTML which is creating ...
Microdata can only be used on HTML elements as defined by HTML5. According to HTML5, the svg element is not in the HTML namespace. WHATWG’s HTML spec explicitly mentions that Microdata doesn’t work for svg (quoted on 2014-01-02):
Currently, the itemscope, itemprop, and other microdata attributes are only defined for HTML elements. This means that ...
The reason it was marked invalid is because it was deprecated, i.e. at the time you tested it was no longer part of the current HTML spec.
It's now been reintroduced to the HTML5 spec, albeit with a different use. Helpful discussion here.
While there is a relationship, technical validity and desirability or efficacy for the purposes of SEO are not ...
The non-normative section 220.127.116.11 Configuring a form to communicate with a server explicitly says that it is valid:
Multiple controls can have the same name; for example, here we give all the checkboxes the same name, and the server distinguishes which checkbox was checked by seeing which values are submitted with that name — like the radio ...
Because there is no controlslist attribute on the audio element in the current official HTML5 standard.
FWIW I can't find any mention of a controlslist attribute on the audio element. The linked question refers to a controlsList*1 attribute on the video element (although I would expect all media elements to share the same attributes).
(*1 The linked question ...
In HTML5+Microdata, only the meta element can have the content attribute.
(In HTML5+RDFa, every element may have the content attribute.)
So if you want to add the string value "in_stock", and it should not be visible on the page, using the meta element is the correct choice:
<meta itemprop="availability" content="in_stock" />
You were probably ...
Google does not take W3C Validation into account for SEO.
From the Official Google Webmaster's Youtube Channel,
(taken via the video's transcript)
And while it's great to make valid code, and it can be easier to
maintain if you know that all your nesting is in good shape and
everything validates, we have to crawl and index and return results on
W3C Validity is not a direct ranking factor however several errors the validator may return for your website are considered as good practices for SEO. Problems like wrongly nested or placed tags can make your content impossible to crawl. Search Engines do a very good job to find their ways through the content inside non-standard or problematique code however ...
Another alternative would be to save your image as a .svg file. You can use any text editor to create this file and paste in your SVG markup. Then put the markup on just like you would do for a .png or .jpg:
<div itemscope itemtype="http://schema.org/Organization">
<a itemprop="url" href="http://www.example.com/">Home</a>
You can simply refer to Your logo via meta/link tag as suggested in official documentation: http://schema.org/docs/gs.html#advanced_missing
<!-- schema.org item wrapper -->
<div itemscope itemtype="http://schema.org/Organization">
<!-- This is Your original SVG markup -->
<svg id="my-logo" height="60" width="60" xmlns="http://www.w3....
The title attribute is available to all HTML tags:
HTML defines a few attributes that are common to all HTML elements. These attributes can be used on all elements, though the attributes may have no effect on some elements.
So you can safely put it on any element you want. But it is up to the browser to determine if it will do anything with that ...
The meta element can’t have a src attribute, and if it appears in the body, it must have a content attribute.
If the value is a URL, you must use the link element instead of the meta element:
<link property="" href="" />
Include a reference link in your <head></head> the same way you
would link your CSS file:
<link rel="stylesheet" href="https://fonts.googleapis.com/icon?family=Material+Icons">
Reference your <icon> as <i class="material-icons">cloud</i>
You can learn more about it at W3Schools Icon Tutorial
W3C errors (css or html) increase the chances of your site not rendering correctly across all devices.
You should worry about the css errors and get them fixed.
There is an awesome W3C Validator Chrome plugin that makes troubleshooting easy.
Please, check Joey's answer on this:
If your HTML is going to be regularly processed by automated tools
instead of being read by humans, then you might want to use XHTML
because of its more strict structure and being XML it's more easy to
parse (from an application standpoint. Not that XML is inherently easy
to parse, though).
You can see all the ...
The example is invalid HTML+Microdata. It is not allowed to have the itemprop attribute on meta[name] or link[rel] elements.
The solution for HTML+Microdata would be to duplicate the elements:
<head itemscope itemtype="http://schema.org/WebSite">
<title itemprop="name">Example.com - Best Website in the World</title>
The W3C mobile validator reports errrors, cautions and informational based results. It's extremely likely and common for websites to have cautions. When W3C reports a caution it does not mean your site is broken.
Break down of result types:
Critical Error(s): X
Severe Error(s): -
Medium Error(s): ...
Low Error(s): .
Title is common to all elements:
However, it is worth paying notice of the warning on this page:
Relying on the title attribute for the visual display of text
content is currently discouraged as many user ...
The data-* attributes are defined for (X)HTML5 only.
The Microdata attributes (itemscope, itemprop, …) are defined for (X)HTML5 only.
So when you switch to (X)HTML5, you can use both of these.
If you want to keep using XHTML 1.0, you could use class instead of data-* attributes, and RDFa instead of Microdata (which requires adjusting your DOCTYPE).
Your problem is that CSS with <link> should be placed within <head> </head> and not within the tags <body> </body>. This should fix your validation problems.
<title>Your Page Title</title>
<link media="all" rel="...
Solving validation errors in your site's HTML code will NOT help your rankings in search engines.
Here is a video where Matt Cutts weights in on the situation:
Matt: Hi. We have a guest to answer today’s webmaster video question. The question comes from Jimmy @Feldon, Wirsberg. Nice job getting your Twitter handle in there by the way. Jimmy asks, “Hi ...
You must be copying the pagespeed markup into the validator or validating from that page. If you want to get a valid report, you must point the validator to your page and not at the markup in the toolbar (assuming that's what you're doing). Pagespeed does not insert anything into your server markup.
I wouldn't worry about those errors. I'm not sure why pagespeed is putting those attributes in, but they don't seem to be hurting anything other than causing validation warnings.
As far as SEO goes Google Says Pages That Validate Do Not Get Ranking Boost. So having a few validation problems won't cause any problems on that front.
A lot of those "errors" are their use of deprecated or obsolete markup but that markup is for older browsers and mobile devices that won't work well without it. Removing the obsoleted markup knocks that number down quite a bit.
While there are some flat out errors in there, if it's not intentional to help old browsers and devices along, are probably just ...