To show a hidden HTML element using JavaScript, you can change the CSS property display of the element to a visible value. Here is an example:
HTML:
<div id="myElement" style="display: none;">Hello, this is a hidden element!</div>
JavaScript:
// Get the element by its ID
var element = document.getElementById("myElement");
// Set the display property to a visible value
element.style.display = "block";
In this example, the CSS property display of the element with ID "myElement" is set to "none", which hides the element by default. By changing the display property to "block" or any other visible value such as "inline" or "flex", the element will become visible.