<!DOCTYPE html>
<html>
<body>
<img src="planets.gif" width="145" height="126" usemap="#planetmap">
<map name="planetmap">
<area id="venus" target="_blank" shape="circle" coords="124,58,8" alt="Venus" href="../../www.example.com:80/test.htm">
</map>
<p>Click the button to change the port number of the href attribute for the "venus" area in the image-map.</p>
<p><b>Tip:</b> Open the "venus" area and look in the address bar before and after you have clicked the "Try it" button (the new example link is just a demonstration, and will not work).</p>
<button onclick="myFunction()">Try it</button>
<p id="demo"></p>
<script>
function myFunction() {
document.getElementById("venus").port = "443";
document.getElementById("demo").innerHTML = "The port number was changed from '80' to '443'.";
}
</script>
</body>
</html>