debug.js

// save old function
$.ajaxOld = $.ajax;

// replace ajax call with our own that adds the delay
$.ajax = function() {
  // save state from the original function call for use later
  var args = [].slice.call(arguments);
  var self = this;

  // call the original ajax function in 1.5 seconds
  setTimeout(function() {
      $.ajaxOld.apply(self, args);
  }, 1500);
};