how to make round background image buttons in CSS and JavaScript code example

Example 1: round button css

.btn {
  display:block;
  height: 300px;
  width: 300px;
  border-radius: 50%;
  border: 1px solid red;
  
}

Example 2: how to round the edges of an image in HTML

img.rounded-corners {
  border-radius: 30px;
}