JSFiddle - React, Tailwind, and code Playground

HTML

<body>
    <button onclick="run()">Run example</button>
</body>

JavaScript

function ajax(varia) {
    
    return $.ajax({

        dataType: "html",
        async: false,
        type: 'POST',
        url: '/echo/html/',
        data: {
            html: '<p id="login" style="display:none">Test HTML</p>',
            delay: 1
        }

    });
    
}

function run() {
    ajax("login").done(function (data) {
    
        $("body").prepend(data);
    
        // The #login have atribute style="display: none;"
        $("#login").fadeIn(500); 
    
    });
}