JSFiddle - React, Tailwind, and code Playground

HTML

<input type="text"  id="a" value="1st" />
<input type="text"  id="b" value="2nd" />
<input type="text"  id="c" value="3rd" />
<input type="text"  id="d" value="4th" />
<input type="button"  id="go" onclick="swapValues()" value="Swap">

JavaScript

function swapValues(){
var tmp = document.getElementById("c").value;
document.getElementById("c").value = document.getElementById("d").value;
document.getElementById("d").value = tmp;
    
}