Defence24.com W3C HTML Markup Validation
HTML markup errors and warnings
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Warnings:
Consider avoiding viewport values that prevent users from resizing documents.
Section lacks heading. Consider using “h2”-“h6” elements to add identifying headings to all sections.
Attribute “twitterze"” is not serializable as XML 1.0.
Errors:
A document must not include more than one “meta” element with its “name” attribute set to the value “description”.
Duplicate attribute “data-id”.
Element “div” not allowed as child of element “h2” in this context. (Suppressing further errors from this subtree.)
Quote “"” in attribute name. Probable cause: Matching quote missing somewhere earlier.
Attribute “udostępnij” not allowed on element “a” at this point.
Attribute “na” not allowed on element “a” at this point.
Attribute “twitterze"” not allowed on element “a” at this point.
The “aria-labelledby” attribute must point to an element in the same document.
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