With the following HTML, how can I select all divs at parent level only, except div with attribute - class="first" and its children using JavaScript?

In other words, after calling a query I want to get an array with these divs: class="all", class="second" and class="third".

<div class="all">
    <div class="header">All</div>
    <div class="cell-1"></div>
    <div class="cell-2"></div>
    <div class="cell-3"></div>
    <div class="cell-4"></div>
</div>
<div class="first">
    <div class="header">First</div>
    <div class="cell-1"></div>
    <div class="cell-2"></div>
    <div class="cell-3"></div>
    <div class="cell-4"></div>
</div>
<div class="second">
    <div class="header">Second</div>
    <div class="cell-1"></div>
    <div class="cell-2"></div>
    <div class="cell-3"></div>
    <div class="cell-4"></div>
</div>
<div class="third">
    <div class="header">Third</div>
    <div class="cell-1"></div>
    <div class="cell-2"></div>
    <div class="cell-3"></div>
    <div class="cell-4"></div>
</div>

These divs are children of some container (body at least, if not something more immediate). So you can use a selector with a child combinator and a :not clause for the .first element you don't want:

var divs = document.querySelectorAll("body > div:not(.first)");

Of course, if body isn't their container, replace that with a selector for the element that is.

Example:

var divs = document.querySelectorAll("body > div:not(.first)");
console.log("matching elements: " + divs.length);
Array.prototype.forEach.call(divs, function(div, index) {
  console.log(index + ": " + div.className);
});

<div class="all">
  <div class="header">All</div>
  <div class="cell-1"></div>
  <div class="cell-2"></div>
  <div class="cell-3"></div>
  <div class="cell-4"></div>
</div>
<div class="first">
  <div class="header">First</div>
  <div class="cell-1"></div>
  <div class="cell-2"></div>
  <div class="cell-3"></div>
  <div class="cell-4"></div>
</div>
<div class="second">
  <div class="header">Second</div>
  <div class="cell-1"></div>
  <div class="cell-2"></div>
  <div class="cell-3"></div>
  <div class="cell-4"></div>
</div>
<div class="third">
  <div class="header">Third</div>
  <div class="cell-1"></div>
  <div class="cell-2"></div>
  <div class="cell-3"></div>
  <div class="cell-4"></div>
</div>