timestamp.js

$.post('https://chat.stackexchange.com/chats/20298/events', 
       { msgCount:100, 
         since:0, 
         mode: 'Messages', 
         fkey: $("input[name='fkey']").attr("value") 
       }, 
       function(data){ 
        console.log(data); 
        var ts = parseInt(data.events[0].time_stamp,10); 
        for(var i=0;i<100;i++){ 
          var c = parseInt(data.events[i].time_stamp); 
          console.log(c - ts); ts=c; 
        } 
      });