Swaping elements in js(drag and drop)

Question

Can somebody help to understand swapping elements? I know basics of dragging and dropping but can't do swapping.

Answer 1

https://code.sololearn.com/Whq9rPnTy5BK/?ref=app
In this old code of mine I have used a swap function.
function swap()
{

var a = document.getElementById('first').value;

document.getElementById('first').value = document.getElementById('second ').value;

document.getElementById('second').value = a;

}

I hope I have been helpful.