css transition width code example

Example 1: css transition all

-webkit-transition: all .3s ease-in-out;
-moz-transition:    all .3s ease-in-out;
-o-transition:      all .3s ease-in-out;
-ms-transition:     all .3s ease-in-out;
transition:         all .3s ease-in-out;

Example 2: css opacity transition

div {
  transition: opacity seconds;
}