main.js

var images = [

    "https://pbs.twimg.com/media/EaUCSPLUMAEPiIf.jpg",
    "https://i.ytimg.com/vi/aAE02ZN3T9g/maxresdefault.jpg",
    "https://qph.fs.quoracdn.net/main-qimg-df1c7310a2024cd4e71c17ebc4cef19f.webp"

  ]

  var imageHead = document.getElementById("tc");
  var i = 0;
setInterval(function() {
      imageHead.style.backgroundImage = "url(" + images[i] + ")";
      imageHead.style.opacity="0.9";
      imageHead.style.transitionDuration="1s"
      imageHead.style.backgroundRepeat="no-repeat"
      imageHead.style.position="relative";
      imageHead.style.backgroundAttachment="fixed";
      imageHead.style.minHeight="50vh"
      imageHead.style.backgroundSize="cover";

      i = i + 1;
      if (i == images.length) {
        i =  0;
      }
}, 2000);



$(window).scroll(function(){
  var height = $(window).scrollTop();
  if (height > 260) {
    $('.gotop').fadeIn();
  }else {
    $('.gotop').fadeOut();
    }
 });