Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<head>
<style> 
#myDIV {
    margin: auto;
    border: 1px solid black;
    outline: coral solid 5px;
    width: 300px;
    height: 300px;
    -webkit-animation: mymove 5s infinite; /* Chrome, Safari, Opera */
    animation: mymove 5s infinite;
}

/* Chrome, Safari, Opera */
@-webkit-keyframes mymove {
    50% {outline-width: 50px;}
}

/* Standard syntax */
@keyframes mymove {
    50% {outline-width: 50px;}
}
</style>
</head>
<body>

<p>Gradually change the outline-width property from 5px to 50px and back to 5px:<p>
<div id="myDIV"></div>

<p>The outline-width property is <em>animatable</em> in CSS.</p>
<p><strong>Note:</strong> CSS Animations do not work in Internet Explorer 9 and earlier versions.</p>

</body>
</html>