JSFiddle - React, Tailwind, and code Playground

HTML

<form onsubmit="return testSubmit(this)" action="javascript:;">
    
    <input type="submit" value="Annuler" onclick="clickedButton=this"/>
    <input type="submit" value="Envoyer" onclick="clickedButton=this"/>
</form>

JavaScript

var clickedButton;
function testSubmit(form) {
    alert(clickedButton.value)
}