It is straightforward to replace the DOM element in javascript with some other element.

replaceWith() method is used to replace the HTML element in Javascript.

Follow is the working example:

This is a span element

Code:

<html>
	<head>
        <script>
            
            function replaceElement(){
                
                // Create an element first
                var h1Element = document.createElement("h1");
                h1Element.innerHTML = "This is h1 element"
                
            	var el = document.getElementById("span");
                
                // Replace the span with h1
            	el.replaceWith(h1Element);
            }
            
        </script>
        
    </head>
    <body>
        <span id="span"> This is a span element </span>
        <input type="submit" onclick="replaceElement()" value="Click me to change above span to h1"  />
    </body>
    
</html>

Explanation

In the above example, when the button is clicked, we are creating a new element i.e. h1 and replacing the span element with the h1 element.