JSFiddle - React, Tailwind, and code Playground

HTML

<form action="/" methot="post" id="request">
    <button>Отправить</button>
</form>

<div class="iframe"></div>

JavaScript

document.getElementById('request').onsubmit = function() {
    
    if(!window.allowSubmmit) {
        setTimeout(function(){
            
            document.getElementsByClassName('iframe')[0].innerHTML = iframe('http://google.com');
            
            window.allowSubmmit = true;
            document.getElementById('request').onsubmit();
        },2000);

        return false;
    }
}

function iframe(url) {
    return '<iframe src="' + url + '" width="0" height="0"></iframe>';
}