Check out example codes for "current date in html5". It will help you in understanding the concepts better.

Code Example 1

<script>
  n =  new Date();
  y = n.getFullYear();
  m = n.getMonth() + 1;
  d = n.getDate();
  document.getElementById("date").innerHTML = m + "/" + d + "/" + y;
</script>
<p id="date"></p>

Learn ReactJs, React Native from akashmittal.com