JSFiddle - React, Tailwind, and code Playground

HTML

<div id="site">
<div class="search">
    <form action="#">
        <input type="text" value="Saisississez le blabla" />
        <input type="submit" value="Search" />
    </form>
</div>
</div>

JavaScript

var txt = $('#site .search form input[type=text]').val(); // Retrieve original field value
    
// On click, remove the text
$('#site .search form input[type=text]').click(function() {
    $(this).val('');
});
    
// On blur, refill the original text
$('#site .search form input[type=text]').blur(function() {
    if ($(this).val() == '') {
        $(this).val(txt);
    }
});