Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<head>
<style>body {
    background-image: url('img_tree.png');
    background-repeat: no-repeat;
}
</style>
</head>
<body>

<button type="button" onclick="myFunction()">Position background image</button>

<script>
function myFunction() {
    document.body.style.backgroundPosition="top right"; 
}
</script>

</body>
</html>