Errors:
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”.
No space between attributes.
Quote “"” in attribute name. Probable cause: Matching quote missing somewhere earlier.
Bad value “//www.googletagmanager.com/ns.html?id=GTM-T378N7 height=” for attribute “src” on element “iframe”: Illegal character in query: space is not allowed.
Attribute “0"” not allowed on element “iframe” at this point.
Bad value “” for attribute “target” on element “a”: Browsing context name must be at least one character long.
Bad value “” for attribute “border” on element “img”: Only “0” is a permitted zero literal.
An “img” element must have an “alt” attribute, except under certain conditions. For details, consult guidance on providing text alternatives for images.
Bad value “” for attribute “id” on element “a”: An ID must not be the empty string.
Duplicate ID “”.
Element “a” not allowed as child of element “ul” in this context. (Suppressing further errors from this subtree.)
Duplicate ID “mobile-menu”.
Duplicate ID “download_brochures_link”.
Duplicate ID “searchForm”.
Bad value “” for attribute “id” on element “div”: An ID must not be the empty string.
Duplicate ID “emblematic_works_page_link”.
Attribute “null” not allowed on element “a” at this point.
Warnings:
Attribute “0"” is not serializable as XML 1.0.
The “border” attribute is obsolete. Consider specifying “img { border: 0; }” in CSS instead.
The document is not mappable to XML 1.0 due to two consecutive hyphens in a comment.
Empty heading.
The first occurrence of ID “” was here.
The first occurrence of ID “mobile-menu” was here.
The first occurrence of ID “download_brochures_link” was here.
The first occurrence of ID “searchForm” was here.
Consider using the “h1” element as a top-level heading only (all “h1” elements are treated as top-level headings by many screen readers and other tools).
Section lacks heading. Consider using “h2”-“h6” elements to add identifying headings to all sections.
The first occurrence of ID “emblematic_works_page_link” was here.
Czech Republic CZ