<!DOCTYPE html>
<html>
<head>
<style>
#main {
width: 350px;
height: 100px;
border: 1px solid #c3c3c3;
display: flex;
}
#main div:nth-of-type(1) {flex-grow: 1;}
#main div:nth-of-type(2) {flex-grow: 1;}
#main div:nth-of-type(3) {flex-grow: 1;}
#myBlueDiv {
-webkit-animation: mymove 5s infinite; /* Chrome, Safari, Opera */
animation: mymove 5s infinite;
}
/* Chrome, Safari, Opera */
@-webkit-keyframes mymove {
50% {flex-grow: 8;}
}
/* Standard syntax */
@keyframes mymove {
50% {flex-grow: 8;}
}
</style>
</head>
<body>
<p>Gradually change the flex-grow property of the "blue DIV" from 1, to 8, and back to 1:<p>
<div id="main">
<div style="background-color:coral;"></div>
<div style="background-color:lightblue;" id="myBlueDiv"></div>
<div style="background-color:khaki;"></div>
</div>
<p>The flex-grow property is <em>animatable</em> in CSS.</p>
<p><b>Note:</b> CSS Animations do not work in Internet Explorer 9 and earlier versions.</p>
</body>
</html>