<!DOCTYPE html>
<html>
<head>
<style>
#myDiv {
border: 1px solid #FF0000;
position: relative;
}
</style>
</head>
<body>
<div id="myDiv">This is a div element.</div>
<br>
<button type="button" onclick="myFunction()">Set right position of div to -100 px</button>
<script>
function myFunction() {
document.getElementById("myDiv").style.right = "-100px";
}
</script>
</body>
</html>