JavaScript Tutorial/Document/title
Assign value to the document title (you must have the title tag in your html document)
<html>
<head>
<title>Untitled</title>
<script language="javascript" type="text/javascript">
function changeTitle()
{
var newTitle = prompt("A title.", "default title");
window.document.title = newTitle;
}
</script>
</head>
<body>
<P>You can change <a href="javascript:changeTitle()">
the <title> element</a> on this page</p>
</body>
</html>
document.title
The title property is a read-only string that specifies the title of the document.
This property is commonly set with the tag.
<html>
<head><title>My Web Page</title></head>
<script>
<!--
document.write("The title of this page is <i>");
document.write(document.title,"</i>");
-->
</script>
</html>