Why Double-Click for Show/Hide Button on First Use?

In a web page, a button is intended to show or hide an element, but it requires a double-click on its initial invocation. Upon examination, the code for the button is found to be:

function showhidemenu() {
  var x = document.getElementById("menu");
  if (x.style.display === "none") {
    x.style.display = "block";
  } else {
    x.style.display = "none";
  }
}

The issue stems from the initial state of the element with ID "menu." By default, the element's display property is set to "none" in the CSS. When the showhidemenu() function is called for the first time, the following check is performed:

if (x.style.display === "none")

This check evaluates to true because the initial display property of the element is "none." Consequently, the element's display is set to "block." However, on the next click, the display property is set to "none" as expected.

To address this issue, the initial display property of the element should be set to "empty" instead of "none." Doing so ensures that the check in the function is evaluated correctly on the first click.

if (x.style.display === "none" || x.style.display === "")

With this modification, the button will show the element on the first click, as intended.