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<html><head><style> #myDIV { width: 300px; height: 200px; border: 1px solid black; background-image: url('smiley.gif'); background-position-y: top; animation: mymove 5s infinite;}@keyframes mymove { 50% {background-position-y: center;}}</style></head><body><h1>Animation of background-position-y</h1><p>Gradually change the background-position-y from "top" to "center", and back to "top":<p><div id="myDIV"></div></body></html>