Errors:
Attribute “xmlns:content” not allowed here.
Attribute “xmlns:dc” not allowed here.
Attribute “xmlns:foaf” not allowed here.
Attribute “xmlns:og” not allowed here.
Attribute “xmlns:rdfs” not allowed here.
Attribute “xmlns:sioc” not allowed here.
Attribute “xmlns:sioct” not allowed here.
Attribute “xmlns:skos” not allowed here.
Attribute “xmlns:xsd” not allowed here.
When the attribute “xml:lang” in no namespace is specified, the element must also have the attribute “lang” present with the same value.
The “version” attribute on the “html” element is obsolete. You can safely omit it.
A document must not include both a “meta” element with an “http-equiv” attribute whose value is “content-type”, and a “meta” element with a “charset” attribute.
A “meta” element with an “http-equiv” attribute whose value is “X-UA-Compatible” must have a “content” attribute with the value “IE=edge”.
Bad value “” for attribute “name” on element “input”: Must not be empty.
Attribute “value” not allowed on element “input” at this point.
Attribute “about” not allowed on element “div” at this point.
Attribute “content” not allowed on element “span” at this point.
An “img” element must have an “alt” attribute, except under certain conditions. For details, consult guidance on providing text alternatives for images.
Attribute “datatype” not allowed on element “span” at this point.
Bad value “Nu op Twitter” for attribute “id” on element “div”: An ID must not contain whitespace.
Duplicate attribute “class”.
Warnings:
Attribute with the local name “xmlns:content” is not serializable as XML 1.0.
Attribute with the local name “xmlns:dc” is not serializable as XML 1.0.
Attribute with the local name “xmlns:foaf” is not serializable as XML 1.0.
Attribute with the local name “xmlns:og” is not serializable as XML 1.0.
Attribute with the local name “xmlns:rdfs” is not serializable as XML 1.0.
Attribute with the local name “xmlns:sioc” is not serializable as XML 1.0.
Attribute with the local name “xmlns:sioct” is not serializable as XML 1.0.
Attribute with the local name “xmlns:skos” is not serializable as XML 1.0.
Attribute with the local name “xmlns:xsd” is not serializable as XML 1.0.
This document appears to be written in Dutch. Consider adding “lang="nl"” (or variant) to the “html” start tag.
Netherlands NL