JSFiddle - React, Tailwind, and code Playground

HTML

<p>This is some random text in a paragraph with a <span class="blue">blue</span> word.</p>
<p>This is some random text in a paragraph with a <span class="blue">blue</span> <i>word</i>.</p>
<p>This is some random text in a paragraph with a <span class="blue">blue</span> <span class="blue">word</span>.</p>

CSS

.blue{
    color:blue;
}
.popup{
    background-color:lightblue;
}

JavaScript

var popup = false;
$(".blue").click(function() {
    if (!popup) {
        $(this).append("<div class='popup'>This is some popup text</div>");
        popup = true;
    } else{
        $(".popup").remove();
        popup = false;
    }
});