how to make in image to fill the background code example

Example 1: CSS make image fill whole background

html { 
  background: url(images/bg.jpg) no-repeat 
    center center fixed; 
  -webkit-background-size: cover;
  -moz-background-size: cover;
  -o-background-size: cover;
  background-size: cover;
}

Example 2: css fill div with background image

div {
  background-image: url("example.com/image.png");
  background-size: 100% 100%;
}