Materialeducativo.org W3C HTML Markup Validation
HTML markup errors and warnings
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Errors:
Bad value “https://api.w.org/” for attribute “rel” on element “link”: The string “https://api.w.org/” is not a registered keyword.
The “center” element is obsolete. Use CSS instead.
Stray end tag “head”.
Start tag “body” seen but an element of the same type was already open.
The “scrolling” attribute on the “iframe” element is obsolete.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The “frameborder” attribute on the “iframe” element is obsolete.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The “allowtransparency” attribute on the “iframe” element is obsolete. Use CSS instead.
Bad value “1” 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 “_new” for attribute “target” on element “a”: Reserved keyword “new” used.
Warnings:
The “border” attribute is obsolete. Consider specifying “img { border: 0; }” in CSS instead.
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