Tryit Editor v2.9

Edit This Code:
<!DOCTYPE html>
<html>
<head>
<style>
#test {
  top: 100px;
  margin: 10px;
  padding: 10px;
  width: 300px;
  position: relative;
  border: 5px solid black
}
</style>
</head>
<body>
<div id="test">
<p>Click the button to get offsetTop for the test div.</p>
<p><button onclick="myFunction()">Try it</button></p>
<p>offsetTop is: <span id="demo"></span></p>
</div>
<script>
function myFunction() {
    var testDiv = document.getElementById("test");
    document.getElementById("demo").innerHTML = testDiv.offsetTop;
}
</script>

</body>
</html>