JSFiddle - React, Tailwind, and code Playground

HTML

<input type='checkbox' id='check' /> Show Password
<br />
<input type='password' id='password' />
<input type='text' id='plaintext' style='display: none'; />

JavaScript

$(document).ready(function() {
    $('#check').click(function() {
        if ($(this).attr('checked')) {
            $('#plaintext').show().val($('#password').val());
            $('#password').hide();
        } else {
            $('#password').show().val($('#plaintext').val());
            $('#plaintext').hide();
        }
    });
});