<html>
<head>
<style>
div
{
background-image: url('img_tree.png');
background-repeat: no-repeat;
width: 400px;
height: 400px;
border: 1px solid #000000;
}
</style>
<script>
function displayResult()
{
document.getElementById("div1").style.backgroundPosition="center bottom";
}
</script>
</head>
<body>
<button type="button" onclick="displayResult()">Position background image</button>
<br>
<div id="div1">
</div>
</body>
</html>