JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li>Don't ROT13 this text.</li>
    <li class="spoilerText">This text should be obfuscated.</li>
    <li>Part of this text <span class="spoilerText">should be obfuscated</span>.</li>
</ul>

CSS

.spoilerText {
    cursor: pointer;
    background: #ff0;
}

JavaScript

function rot13(s) {
    // credit: http://stackoverflow.com/a/617685/1481489
    return s.replace(/[a-zA-Z]/g,function(c) {
        return String.fromCharCode((c<="Z"?90:122)>=(c=c.charCodeAt(0)+13)?c:c-26);
    });
};

$('.spoilerText').each(function(s) {
    var $this = $(this);
    $this.text(rot13($this.text()));
}).click(function() {
    var $this = $(this);
    $this.text(rot13($this.text()));
});