Errors:
Legacy doctype. Expected “<!DOCTYPE html>”.
Attribute “xmlns:fb” not allowed here.
Attribute “xmlns:og” not allowed here.
Attribute “xmlns:article” not allowed here.
Attribute “xmlns:book” not allowed here.
Attribute “xmlns:profile” not allowed here.
Attribute “xmlns:video” not allowed here.
Attribute “xmlns:product” 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The “version” attribute on the “html” element is obsolete.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.
The “profile” attribute on the “head” element is obsolete. To declare which “meta” terms are used in the document, instead register the names as meta extensions. To trigger specific UA behaviors, use a “link” element instead.
An “img” element must have an “alt” attribute, except under certain conditions. For details, consult guidance on providing text alternatives for images.
Element “use” not allowed as child of element “div” in this context. (Suppressing further errors from this subtree.)
Bad value “https://ppe.mercatus.org/research?pub-type[0]=5&pub-type[1]=16” for attribute “href” on element “a”: Illegal character in query: “[” is not allowed.
Bad value “100%” for attribute “width” on element “iframe”: Expected a digit but saw “%” instead.
The “scrolling” attribute on the “iframe” element is obsolete. Use CSS instead.
The “frameborder” attribute on the “iframe” element is obsolete. Use CSS instead.
Bad value “/research?pub-type[0]=22” for attribute “href” on element “a”: Illegal character in query: “[” is not allowed.
Bad value “/research?pub-type[0]=13” for attribute “href” on element “a”: Illegal character in query: “[” is not allowed.
Warnings:
Attribute with the local name “xmlns:fb” 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:article” is not serializable as XML 1.0.
Attribute with the local name “xmlns:book” is not serializable as XML 1.0.
Attribute with the local name “xmlns:profile” is not serializable as XML 1.0.
Attribute with the local name “xmlns:video” is not serializable as XML 1.0.
Attribute with the local name “xmlns:product” is not serializable as XML 1.0.
Attribute “xlink:href” is not serializable as XML 1.0.
The “navigation” role is unnecessary for element “nav”.
The “main” role is unnecessary for element “main”.
Section lacks heading. Consider using “h2”-“h6” elements to add identifying headings to all sections.
United States US