Sonic-pi.net W3C HTML Markup Validation
HTML markup errors and warnings
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Errors:
Text not allowed in element “ul” in this context.
Element “h2” not allowed as child of element “em” in this context. (Suppressing further errors from this subtree.)
An “img” element must have an “alt” attribute, except under certain conditions. For details, consult guidance on providing text alternatives for images.
The “frameborder” attribute on the “iframe” element is obsolete. Use CSS instead.
Attribute “webkitallowfullscreen” not allowed on element “iframe” at this point.
Attribute “mozallowfullscreen” not allowed on element “iframe” at this point.
No “p” element in scope but a “p” end tag seen.
Duplicate ID “demo”.
The “center” element is obsolete. Use CSS instead.
Element “pre” not allowed as child of element “code” in this context. (Suppressing further errors from this subtree.)
Warnings:
Section lacks heading. Consider using “h2”-“h6” elements to add identifying headings to all sections.
The first occurrence of ID “demo” was here.
This document appears to be written in English. Consider adding “lang="en"” (or variant) to the “html” start tag.
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