JSFiddle - React, Tailwind, and code Playground

HTML

<h1 class="trans">Animate my letter spacing</h1>
<input type="button" value="animate" id="btn">
<p>Transition does not work in Firefox v26.

CSS

.trans {
    
    -moz-transition: all 1s;
    transition: all 1s
    
}

.spaced {
    
    letter-spacing: 10px
    
}

JavaScript

$("#btn").on('click', function() {

    $("h1").toggleClass("spaced");

});