JSFiddle - React, Tailwind, and code Playground

HTML

<div>
            <input type="button" value="show" id="show"/>
        </div>
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CSS

#fade {
    display: none;
    background: black;
    opacity:0.4;
    filter:alpha(opacity=50);
    z-index: 1;
    position: fixed;
    left: 0; top: 0;
    width: 100%; height: 100%;
}

#window {
    width: 440px;
    height: 356px;
    background: white;
    position:fixed;
    left:50%;
    top:30%;
    margin:-70px 0 0 -245px;
    z-index: 2;
}

JavaScript

$(document).ready( function() {
                $('#show').click( function() {
                    $("<div id='fade'></div>").appendTo('body');
                    $('#fade').fadeIn('fast');
                });

                $(document).on("click","#fade", function() {
                    $('#fade').remove();
                });
            });