JSFiddle - React, Tailwind, and code Playground

HTML

<form action="javascript:void(0)" id="2" method="post">
     <input type="submit" id="btn_id" value="Submit" />
</form>
<form action="javascript:void(0)" id="6" method="post">
     <input type="submit" id="btn_id1" value="Submit1" />
</form>

JavaScript

$('form').on('submit', function() {
     $elem = $(this);
    alert($elem.attr('id'));
        var id = $elem.children('input[type="submit"]').attr('id');
        if(window.console){
            console.log(" button id = " + id);
        }

});