修改/移动 DOM 中现有的 html 标记（javascript）

Question

I want to move my div class="contentlinks" tag with its content, to place it in the div class="row" after the div class="col-12". Here is the basic html architecture:

<span id="data">
     <section id="" class="thesectionQ">
         <div class="container">
             <div class="row">
                 <div class="col-12">
                     <h1>Title</h1>
                 </div>
            </div>
         </div>
     </section>
     <div class="col-12 contentlinks">
         <a class="btn">link1</a><a class="btn">link2</a>
     </div>
 </span>

Tags are dynamically created in js... my problem is that I can't seem to use appendChild...

my problem is that I can't seem to use appendChild...

I'm trying to target my section with a class="thesectionQ" in a variable as well as my div class="contentlinks" that I want to move:

for example...

   var thedata2 = document.getElementById('data').getElementsByClassName('thesectionQ'); 
   var thedata = document.getElementById('data').getElementsByClassName('contentlinks');
   thedata2.appendChild(thedata);
      

but I have errors... and too often

Answer 1

give section id so it become easy.

document.querySelector('#sectionId div.row')
.appendChild(document.querySelector('div.contentlinks'))