Iuj.ac.jp W3C HTML Markup Validation
HTML markup errors and warnings
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Errors:
Element “title” not allowed as child of element “head” in this context. (Suppressing further errors from this subtree.)
Bad value “https://api.w.org/” for attribute “rel” on element “link”: The string “https://api.w.org/” is not a registered keyword.
Attribute “datetime” not allowed on element “span” at this point.
The “itemtype” attribute must not be specified on elements that do not have an “itemscope” attribute specified.
The “frameborder” attribute on the “iframe” element is obsolete. Use CSS instead.
No “p” element in scope but a “p” end tag seen.
Warnings:
The “banner” role is unnecessary for element “header”.
Document uses the Unicode Private Use Area(s), which should not be used in publicly exchanged documents. (Charmod C073)
The “navigation” role is unnecessary for element “nav”.
Article lacks heading. Consider using “h2”-“h6” elements to add identifying headings to all articles.
Section lacks heading. Consider using “h2”-“h6” elements to add identifying headings to all sections.
The “contentinfo” role is unnecessary for element “footer”.
The “language” attribute on the “script” element is obsolete. You can safely omit it.
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