This attribute, id, defines a unique identifier (ID) which must be unique in the whole document. Its purpose is to identify the element when linking (using a fragment identifier), scripting, or styling (with CSS).
but at book.html we can find duplicates
$ make book
....
$ grep 'id="objectives"' _site/book.html | head -n 2
<h4 id="objectives">Objectives</h4>
<h4 id="objectives">Objectives</h4>
$ grep 'id="objectives"' _site/book.html | wc -l
17
This duplicated id attributes happens due our IPython Notebook lessons since when we convert it to Markdown instead of
From MDN
but at
book.htmlwe can find duplicatesThis duplicated
idattributes happens due our IPython Notebook lessons since when we convert it to Markdown instead ofit use
as you can check here.