Warnings:
The “language” attribute on the “script” element is obsolete. You can safely omit it.
The first occurrence of ID “subnav_1” was here.
The first occurrence of ID “subnav_2” was here.
The first occurrence of ID “subnav_3” was here.
The first occurrence of ID “subnav_4” was here.
The first occurrence of ID “subnav_5” was here.
The first occurrence of ID “subnav_6” was here.
The first occurrence of ID “subnav_7” was here.
The first occurrence of ID “subnav_8” was here.
The first occurrence of ID “challenge_title” was here.
The first occurrence of ID “challenge_content” was here.
This document appears to be written in English. Consider adding “lang="en"” (or variant) to the “html” start tag.
Errors:
An “img” element must have an “alt” attribute, except under certain conditions. For details, consult guidance on providing text alternatives for images.
No space between attributes.
“'” in an unquoted attribute value. Probable causes: Attributes running together or a URL query string in an unquoted attribute value.
Duplicate ID “subnav_1”.
Duplicate ID “subnav_2”.
Duplicate ID “subnav_3”.
Duplicate ID “subnav_4”.
Duplicate ID “subnav_5”.
Duplicate ID “subnav_6”.
Duplicate ID “subnav_7”.
Duplicate ID “subnav_8”.
Element “input” is missing required attribute “alt”.
A table cell was implicitly closed, but there were open elements.
Unclosed element “ul”.
Duplicate ID “challenge_title”.
Duplicate ID “challenge_content”.
Stray end tag “div”.
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