$(document).ready(function() {
  var randomImages = ['bkg1','bkg2','bkg3','bkg5','bkg6','bkg7','bkg8','bkg9','bkg10','bkg11','bkg12','bkg13','bkg14','bkg15','bkg16','bkg17', 'bkg18', 'bkg19'];
  var rndNum = Math.floor(Math.random() * randomImages.length);
  $("html").css({ 
  'background' : "#283b5a url(/images/bkg/" + randomImages[rndNum] + ".jpg) center center fixed no-repeat",
  'background-size' : "cover"
   });
  $("#utility").css({ 
  'background' : "#283b5a url(/images/bkg/" + randomImages[rndNum] + ".jpg) center center fixed no-repeat",
  'background-size' : "cover"
   });

});