h1 {
    background-color: red;
    height: 50px;
    width: 300px;
}
h1:hover {
    -webkit-animation: colorChange 10s;
    -webkit-animation-iteration-count: infinite;
}

@-webkit-keyframes colorChange {
    0% {background-color: red;}
    16% {background-color: blue;}
    33% {background-color: yellow;}
    50% {background-color: green;}
    67% {background-color: orange;}
    83% {background-color: purple;}
    100% {background-color: red;}
}