Using split()
Snippet :
var data =$('#date').text();
var arr = data.split("https://stackoverflow.com/");
$("#date").html("<span>"+arr[0] + "</span></br>" + arr[1]+"https://stackoverflow.com/"+arr[2]);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="date">23/05/2013</div>
Fiddle
When you split this string --->
23/05/2013
on /
var myString = "23/05/2013";
var arr = myString.split("https://stackoverflow.com/");
you’ll get an array of size 3
arr[0] --> 23
arr[1] --> 05
arr[2] --> 2013