The protocol property represents the protocol portion of the URL.
This is located in the beginning of the URL address (the text before ://).
For example, the protocol for http://www.java2s.com is http: and the protocol for ftp://www.yourserver.com is ftp:.
<html>
<head>
<title> Using the protocol property of the Location object</title>
</head>
<body>
<script language="JavaScript">
<!--
function show(){
alert(document.location.protocol);
}
-->
</script>
<form name="form1">
Click the button to get the current location.protocol value of the following address:
<br>
http://www.java2s.com
<br><br>
<input type="button" name="getproto" value="Get protocol" ?onClick='show()'>
<br>
</form>
</body>
</html>