<!DOCTYPE html>
<html>
<body>
<p>
<a href="../html/default.html">HTML</a><br>
<a href="../css/default.html">CSS</a>
</p>
<p>Click the button to add a red border to the first link in the document.</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
document.links[0].style.border = "5px solid red";
}
</script>
</body>
</html>