JSFiddle - React, Tailwind, and code Playground

HTML

<form action="">
                        <div class="emailfooter">
                            <div class="textfooter">Email *</div>
                            <input type="email" placeholder="gngngng." required>
                        </div>
                        <div class="msgfooter">
                            <div class="textfooter">Message *</div>
                            <textarea cols="25" rows="2" placeholder="gngngn" required></textarea>
                        </div>
                        <div class="btnfooter"><button type="submit" class="btnfootersubmit" onclick="popup()">Envoyer</button>
                        </div>
                        </form>

JavaScript

function popup() {
    onclick = alert('test');
}