Syntax
document.links[num].protocol
The protocol property contains the protocol (http:, file:, ftp:, and so on) specified in the URL, including the ending colon (:). This property is a read/write string.
<html>
<map name="colorMap">
<area name="greenArea"
coords="1,1,48,48"
href="http://www.java2s.com"
target="_top">
</map>
<img src="http://www.java2s.com/style/logo.png" align="top"
height="100" width="100" usemap="#colorMap">
<script>
<!--
document.write("protocol = ",document.links[0].protocol);
-->
</script>
</html>