JSFiddle - React, Tailwind, and code Playground
HTML
<form id="nya">
username <input type="text" id="input_username" /><br/>
email <input type="text" id="input_email" /><br/>
hobby <input type="text" id="input_hobby" /><br/>
<input type="submit" />
</form>
JavaScript
$('#nya').submit(function() {
var focusedId = ($("*:focus").attr("id"));
if(focusedId == 'input_email') {
// do your custom stuff here
return false;
}
});