JSFiddle - React, Tailwind, and code Playground

HTML

Form with <code>submit-once</code> class:

<form method="post" class="submit-once" target="_blank">
    <input type="text" autofocus />
    <input type="submit" value="Submit input" />
    <button type="submit">Submit button</button>
</form>

<hr>
    
Form with no class:

<form method="post" target="_blank">
    <input type="text" autofocus />
    <input type="submit" value="Submit input" />
    <button type="submit">Submit button</button>
</form>

JavaScript

$('form.submit-once').submit(function(e){
    if( $(this).hasClass('form-submitted') ){
        e.preventDefault();
        return;
    }
    $(this).addClass('form-submitted');
});