Using SiteNavigationElement in mega menu - html

Question

Guys i have a couple of unclearities.
Am optimising my website for google and i start to use strured data.
First question:
My site have main menu with sub menu and that sub manues have own sub menues etc...
Does all sub menues also need to have declared itemscope itemtype="http://www.schema.org/SiteNavigationElementor just parent need to have?
Check my example below:
<ul itemscope itemtype="http://www.schema.org/SiteNavigationElement">
<li itemprop="name"><a itemprop="url" href="#">Car Parts</a></li>
<li itemprop="name">
<a itemprop="url" href="#">Car Models</a>
<ul itemscope itemtype="http://www.schema.org/SiteNavigationElement" class="dropdown"> <!-- THIS -->
<li itemprop="name"><a itemprop="url" href="#">Sub menu</a></li>
</ul>
</li>
</ul>
Or just need like this
<ul itemscope itemtype="http://www.schema.org/SiteNavigationElement">
<li itemprop="name"><a itemprop="url" href="#">Car Parts</a></li>
<li itemprop="name">
<a itemprop="url" href="#">Car Models</a>
<ul class="dropdown"> <!-- THIS -->
<li itemprop="name"><a itemprop="url" href="#">Sub menu</a></li>
</ul>
</li>
</ul>
Second question
<li itemprop="name"> value of itemprop is name. Does this need to stay with name value or i need to change name => Car Models ?
<a itemprop="url"> does url need to change with my www.example.com/category or just leave url?
Thanks

Answer 1

<ul itemscope itemtype="http://www.schema.org/SiteNavigationElement">
<li itemprop="name"><a itemprop="url" href="#">Car Parts</a></li>
<li class="dropdown">
<a class="dropdown-toggle" href="#">Car Models</a>
<ul class="dropdown-menu">
<li class="nav-item" itemprop="name">
<a class="dropdown-item nav-link" itemprop="url" href="https://stackoverflow.com">stackoverflow</a>
</li>
</ul>
</li>
</ul>
Itemprop should be defined on the navigation items and not the dropdown containers. You also do not need to repeat the schema declaration nor do you need to redeclare the itemscope.
Also, itemprop="" is defining what type of property the dom item is defining. So it should stay as "name" and "url".
here is a Mozilla article explaining itemprop: https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/itemprop