JSFiddle - React, Tailwind, and code Playground
HTML
<input type="text" name="input" id="input" value="123">
<input type="submit" id="submit" value="Отправить">
JavaScript
$('#submit').click(function(){
var inputVal = $('#input').val();
var url = document.location.href;
url.replace(/\/$/,'') + '/';
url += inputVal + '/';
alert(url);
//редирект
//document.location.href = url;
});