Error: Failed to execute ‘appendChild’ on ‘Node’: parameter 1 is not of type ‘Node’

It’s actually a simple answer.

Your function is returning a string rather than the div node. appendChild can only append a node.

For example, if you try to appendChild the string:

var z = '<p>test satu dua tiga</p>'; // is a string 
document.body.appendChild(z);

The above code will never work. What will work is:

var z = document.createElement('p'); // is a node
z.innerHTML = 'test satu dua tiga';
document.body.appendChild(z);