JSFiddle - React, Tailwind, and code Playground
HTML
<form onsubmit="foo();">
<input type="submit" id="submit_button_1" value="Submit button 1">
<input type="submit" id="submit_button_2" value="Submit button 2">
</form>
JavaScript
function foo()
{
//Retrieve the submit button clicked by document.activeElement :
console.log(document.activeElement);
}