stackoverflow-javascript-if-statement-with-boolean

HTML

<!DOCTYPE html>
<html>

  <head>
    <style>
      #myDIV {
        width: 500px;
        height: 500px;
        background-color: lightblue;
        display: none;
      }

    </style>
  </head>

  <body>

    <p>Click the "Try it" button to set the display property of the DIV element:</p>

    <button onclick="myFunction()">Try it</button>

    <div id="myDIV">
      This is my DIV element.
    </div>

    <p><b>Note:</b> The element will not take up any space when the display property set to "none".</p>

    <script>
      var div_aperto = false;

      function myFunction(div_aperto) {

        if (div_aperto) {
          div_aperto = false;
          document.getElementById("myDIV").style.display = "none";
        } else {
          div_aperto = true;
          document.getElementById("myDIV").style.display = "block";
        }

      }

    </script>

  </body>

</html>