title: This in eventHandler equals window type , not element
body: <p>I decided to change <code>onclick</code> events to event listener and got a problem.
  Case a works, and Case b doesn't. Debugger shows that this equals window type, not element</p>
  
  <pre><code>  testName.setAttribute("onclick", "toggleTestsWindow(this)");
  
    // b
    testName.addEventListener("click", () =&gt; toggleTestsWindow(this));
  </code></pre>