Header inside a header? (HTML5) -

this seems strange me oddly there reason use <header> inside <header>.

with <hgroup> remove spec i'm seem @ weird state should/could doing following bit of code.

<header>     <header>         <h1>maecenas faucibus</h1>         <p class="h1-sub">donec sed odio dui.</p>     </header>     <section>         <img src="..." alt="faucibus">         <img src="..." alt="faucibus">         <img src="..." alt="faucibus">     </section> </header> 

this appear in header portion of <article> wonder if visually appear there should still define <header> or should wrap in like:

<section class="article-header">     <header><h1>...</h1><p>...</p></header>     <section>...</section> </section> 

i've not come across said <header> couldn't nesting inside , wondered if same call can have <article> nested in if made logical sense (so if grouped makes sense still itself).

according html5 specification, invalid have <header> element inside <header> element.

it's interesting, because <header> permitted contents technically allow it:

permitted contents -> flow content -> flow elements -> header

however, there constraints specific <header> element - include:

• the header element must not appear descendant of footer element.

• the header element must not appear descendant of address element.

• the header element must not appear descendant of header element.

therefore not valid mark-up - either direct child element or descendant element @ all.