$(document).ready(function() {
  var imgPC = $("#program-pc");
  var imgSP = $("#program-sp");
  var imageStartPC = "images/12_pc.png";
  var imageStartSP = "images/12_sp.png";
  var imageCtaPC = "images/13_pc.png";
  var imageCtaSP = "images/13_sp.png";
  var timerPC = null


  // start image changer for PC after page is loaded
  timerPC = setInterval(function() {
    imgPC.attr("src", (imgPC.attr("src") === imageStartPC) ? imageCtaPC : imageStartPC);
  }, 5000);

  // pause timer and reset to 0 when PC user is hovering over the image
  imgPC.hover(function() {
    if (timerPC !== null) {
      clearInterval(timerPC);
    }
  }, function() {
    timerPC = setInterval(function() {
      imgPC.attr("src", (imgPC.attr("src") === imageStartPC) ? imageCtaPC : imageStartPC);
    }, 5000);
  });

  // start image changer for SP after page is loaded
  setInterval(function() {
    imgSP.attr("src", (imgSP.attr("src") === imageStartSP) ? imageCtaSP : imageStartSP);
  }, 5000);
});