向此幻灯片显示添加过渡

Question

只需按照本教程创建幻灯片：

https://www.youtube.com/watch?v=4YQ4svkETS0&list=PLhAYqyL8bdjy10dbfKoxnO4CXyGR9quCs&index=71&t=0s

有人知道在图像改变时向幻灯片添加过渡效果（例如淡入淡出）的方法吗？使用JavaScript，无需jQuery。

var i = 0 
var images = ["https://images.pexels.com/photos/1152359/pexels-photo-1152359.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940", "https://images.pexels.com/photos/773594/pexels-photo-773594.jpeg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940", "https://images.pexels.com/photos/33109/fall-autumn-red-season.jpg?auto=compress&cs=tinysrgb&dpr=2&h=650&w=940"];
var time = 3000;

function changeImg() {
  document.slide.src = images[i];
  if(i < images.length -1){
    i++;
  } else {
    i = 0;
  }
  setTimeout("changeImg()", time);
}

window.onload = changeImg;

img {
width: 400px;
height: 200px;
}

<img name="slide">