Errors:
Almost standards mode doctype. Expected “<!DOCTYPE html>”.
Bad value “https://www.w3.org/1999/xhtml” for the attribute “xmlns” (only “http://www.w3.org/1999/xhtml” permitted here).
“"” in an unquoted attribute value. Probable causes: Attributes running together or a URL query string in an unquoted attribute value.
The “scrolling” attribute on the “iframe” element is obsolete. Use CSS instead.
The “frameborder” attribute on the “iframe” element is obsolete. Use CSS instead.
The element “iframe” must not appear as a descendant of the “a” element.
Attribute “url” not allowed on element “div” at this point.
Attribute “height” not allowed on element “table” at this point.
The “width” attribute on the “table” element is obsolete. Use CSS instead.
The “valign” attribute on the “td” element is obsolete. Use CSS instead.
The “height” attribute on the “td” element is obsolete. Use CSS instead.
Attribute “defaultvalue” not allowed on element “input” 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.
Bad value “1” for attribute “rel” on element “a”: The string “1” is not a registered keyword.
Bad value “2” for attribute “rel” on element “a”: The string “2” is not a registered keyword.
Bad value “3” for attribute “rel” on element “a”: The string “3” is not a registered keyword.
Bad value “4” for attribute “rel” on element “a”: The string “4” is not a registered keyword.
Bad value “5” for attribute “rel” on element “a”: The string “5” is not a registered keyword.
Bad value “https:///www.instagram.com/gu.verlag” for attribute “href” on element “a”: Unexpected slash or backslash.
Warnings:
Attribute “xmlns” is not serializable as XML 1.0.
The “language” attribute on the “script” element is obsolete. You can safely omit it.
This document appears to be written in German. Consider adding “lang="de"” (or variant) to the “html” start tag.
Germany DE