JSFiddle - React, Tailwind, and code Playground

HTML

a01:<input id="a01" type="text" name="a01">
<br>
a02:<input id="a02" type="text" name="a02">
<hr>
b01:<input id="b01" type="text" name="b01">
<br>
b02:<input id="b02" type="text" name="b02">

JavaScript

$('#a01').live('change', function() {
 var v = $(this).val();
 $('#a02').val(v);
 $(this).val('xxx');
});

$('#b01').change(function() {
 var v = $(this).val();
 $('#b02').val(v);
 $(this).val('yyy');
});