how to add a scrollbar in css code example

Example 1: css scrollbar

::-webkit-scrollbar {
  width: 10px;
}
  ::-webkit-scrollbar-track {
  background: #f1f1f1; 
}
  ::-webkit-scrollbar-thumb {
  background: #888; 
    border-radius:10px;
}
::-webkit-scrollbar-thumb:hover {
  
  background: #555; 
}

Example 2: css no overflow

div.ex1 {
  overflow: scroll;
}

div.ex2 {
  overflow: hidden;
}

div.ex3 {
  overflow: auto;
}

div.ex4 {
  overflow: visible;
}