javascript

Chapter 10: The Document Object Model
❑
❑
IE, Safari 3.1 and later, Opera, and Chrome create a comment node for the first comment but not
for the second. The first comment becomes the first node in document.childNodes .
Firefox as well as Safari prior to version 3.1 ignore both comments.
Once again, the inconsistent behavior makes accessing comments outside the < html > element essentially
useless.
For the most part, the appendChild() , removeChild() , and replaceChild() methods aren ’ t used on
document , since the document type (if present) is read - only and there can be only one element child
node (which is already present).
Document Information
The document object, as an instance of HTMLDocument , has several additional properties that standard
Document objects do not have. These properties provide information about the web page that is loaded.
The first such property is title , which contains the text in the < title > element and is displayed in the
title bar or tab of the browser window. This property can be used to retrieve the current page title as well
as to change the page title such that the changes are reflected in the browser title bar. Changing the value
of the title property does not change the < title > element at all. Here is an example:
//get the document title
var originalTitle = document.title;
//set the document title
document.title = “New page title”;
The next three properties are all related to the request for the web page: URL , domain , and referrer . The
URL property contains the complete URL of the page (the URL in the address bar), the domain property
contains just the domain name of the page, and the referrer property gives the URL of the page that
linked to this page. The referrer property may be an empty string if there is no referrer to the page. All
of this information is available in the HTTP header of the request and is simply made available in
JavaScript via these properties, as shown in the following example:
//get the complete URL
var url = document.URL;
//get the domain
var domain = document.domain;
//get the referrer
var referrer = document.referrer;
The URL and domain properties are related. For example, if document.URL is http://www.wrox.com/
WileyCDA/ , then document.domain will be www.wrox.com .
271