<!DOCTYPE html>
<html>
<body>
<details id="myDetails" open>
<summary>Copyright 1999-2014.</summary>
<p> - by Refsnes Data. All Rights Reserved.</p>
<p>All content and graphics on this web site are the property of the company Refsnes Data.</p>
</details>
<p>Click the "Try it" button to find out if additional details are visible (open) or not.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
let x = document.getElementById("myDetails").open;
document.getElementById("demo").innerHTML = x;
}
</script>
</body>
</html>