//Load jQuery
var jq = document.createElement('script');
jq.src = "https://ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js";
document.getElementsByTagName('head')[0].appendChild(jq);
// ... give time for script to load, then type.
jQuery.noConflict();

var d
$.get("https://www.callbackstaffing.com/Application/Ajax/CrewScheduler/", {start:1438041600,end:1438128000,dataChanged:0},function(data){d=JSON.parse(data.data)})

//Find Engine 24 Crew
d.forEach(function(loc){
  if(loc.title == "Engine 24" && loc.start == "2015-07-27 08:00:00"){
    loc.users.forEach(function(user){
      console.log(user.lastname)
    })
  }
});