JSFiddle - React, Tailwind, and code Playground

HTML

<form>
    <input type="text" id="item1" name="item1" />
    <input type="submit" id="item2" />
</form>
<div id="console"></div>

JavaScript

var $item1 = $('#item1');
var $item2 = $('#item2');
var $console = $('#console');
$item1.on('blur', function (oEvent) {
    if ($item2.is(oEvent.relatedTarget)) {
        $console.append('<p>your blur is caused by click on $item2</p>');
        // your blur is caused by click on $item2 a.k.a submit button
    } else {
        $console.append('<p>your blur is caused by smth else</p>');
        // your blur is caused by smth else
    }
});

$('form').on('submit', function (oEvent) {
    oEvent.preventDefault();
});