Collapse Sidepanel - Add Sub Menus Possible?

[TH71]

Is it possible to add Sub/Dropdown Menus to the Collapse Sidepanel

https://www.w3schools.com/howto/howto_js_collapse_sidepanel.asp

like the Dropdown Menu in Sidenav

https://www.w3schools.com/howto/howto_js_dropdown_sidenav.asp

 

Thanks

[niche]

Everything is possible with code.  what might your code look like if you tried to that? 

[TH71]

Thanks

I have tried all sorts but although still learning I am not exactly great with code

 

I have tried adding

<button class="dropdown-btn">Dropdown
    <i class="fa fa-caret-down"></i>
  </button>
  <div class="dropdown-container">
    <a href="#">Link 1</a>
    <a href="#">Link 2</a>
    <a href="#">Link 3</a>

 into any of the below <a href="#"></a>

<div id="mySidepanel" class="sidepanel">
  <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
  <a href="#">About</a>
  <a href="#">Services</a>
  <a href="#">Clients</a>
  <a href="#">Contact</a>
</div>

but it is does not work