JSFiddle - React, Tailwind, and code Playground

HTML

<div id="content">
   <div id="box1" class="box1class">
     <div>...</div>
   </div>
   <div id="box2" class="box1class">
   <div>...</div>
   </div>
   <div id="box3" class="box1class">
   <div>...</div>
    </div>
</div>

JavaScript

var array =  $("#content > div").map(function(){
       return this.id;
    }).get();
alert(array);