JSFiddle - React, Tailwind, and code Playground

HTML

<p>You'll be automatically redirected in <span id="count">10</span> seconds...</p>

JavaScript

$(function(){
  var counter = 10;

  setInterval(function() {
    counter--;
    if (counter >= 0) {
      span = document.getElementById("count");
      span.innerHTML = counter;
    }
    // Display 'counter' wherever you want to display it.
    if (counter === 0) {
    //    alert('this is where it happens');
        alert(counter);
    }

  }, 1000);

});