JSFiddle - React, Tailwind, and code Playground

HTML

<div id="date">Mon, 15 Jul 2013 09:27:39 -0700</div>
<div id="sol"></div>

JavaScript

var t = $("#date").text();
$("#sol").html(function(){
   var result = "On ";
   var sub = t.substr(0,17);
   t = t.substr(17);
   result += sub + "at ";
   var pre = t.substr(0,2);
   t = t.substr(2,3);
   var suffix = "am";
   if( parseInt(pre) > 11 ){
       suffix = "pm";
       if( pre != 12 ){
         pre = parseInt(pre) - 12;   
       }
   }
   result += pre + t + suffix;
   return result;
});