Channel Definition Format

For other uses of "CDF", see CDF (disambiguation).

Channel Definition Format (CDF) is an XML file format used in conjunction with Microsoft Active Channel and Smart Offline Favorites technologies. Introduced in March 1997, the format is designed to "offer frequently updated collections of information, or channels, from any web server for automatic delivery to compatible receiver programs."^[1] CDF is somewhat similar to the RSS file format introduced by Netscape in 1999. CDF and Active Channel were introduced with the launch of Internet Explorer 4.0 in 1998, while Smart Offline Favorites was introduced with the launch of Internet Explorer 5.0.

Active Channel allows websites to be listed and syndicated with the end-users' desktop. Smart Offline Favorites, like channels, enable users to view webpages from the cache.

However, unlike RSS, the idea of Active Channels was never widely adopted and its use remains very limited. As a direct result, Microsoft has removed CDF support from Internet Explorer 7.

Example

A generic CDF file:

<?xml version="1.0" encoding="UTF-8"?>
<CHANNEL HREF="http://domain/folder/pageOne.extension"
  BASE="http://domain/folder/"
  LASTMOD="1998-11-05T22:12"
  PRECACHE="YES"
  LEVEL="0">
    <TITLE>Title of your Channel</TITLE>
    <ABSTRACT>Synopsis of your channel's contents.</ABSTRACT>
    <SCHEDULE>
      <INTERVALTIME DAY="14"/>
    </SCHEDULE>
    <LOGO HREF="wideChannelLogo.gif" STYLE="IMAGE-WIDE"/>
    <LOGO HREF="imageChannelLogo.gif" STYLE="IMAGE"/>
    <LOGO HREF="iconChannelLogo.gif" STYLE="ICON"/>
    <ITEM HREF="pageTwo.extension"
      LASTMOD="1998-11-05T22:12"
      PRECACHE="YES"
      LEVEL="1">
        <TITLE>Page Two's Title</TITLE>
        <ABSTRACT>Synopsis of Page Two's contents.</ABSTRACT>
        <LOGO HREF="pageTwoLogo.gif" STYLE="IMAGE"/>
        <LOGO HREF="pageTwoLogo.gif" STYLE="ICON"/>
    </ITEM>
</CHANNEL>

See also

• Semantic Web
• List of content syndication markup languages

References

1. ^ Ellerman, Castedo (1997-03-10). "Channel Definition Format Submission 970309". W3.org. http://www.w3.org/TR/NOTE-CDFsubmit.html. Retrieved 2011-07-08. 

External links

• Introduction to Active Channel Technology
• How to Create Channel Definition Format (CDF) Files
• 1997 W3 Submission of Channel Definition Format