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<html><body><img src="planets.gif" width="145" height="126" usemap="#planetmap"><map name="planetmap"> <area id="venus" shape="circle" coords="124,58,8" alt="Venus" href="venus.htm"></map><p>Click the button to change the protocol of the href attribute for the "venus" area in the image-map.</p><button onclick="myFunction()">Try it</button><p id="demo"></p><script>function myFunction() { document.getElementById("venus").protocol = "mailto:"; document.getElementById("demo").innerHTML = "The protocol was changed from 'http://' to 'mailto://'.";}</script></body></html>