AJAX - The Complete Reference

PART IV

Appendix B: HTTP 1.1 Reference 589

NNOT EOTE A CONNECT method is also reserved in HTTP 1.1 to use with a proxy to tell it to act like

a tunnel.

NNOT EOTE Some user-agents may also support the various WebDav (www.webdav.org) methods such as

MOVE, PROPFIND, PROPPATCH, MKCOL, COPY, LOCK, UNLOCK, POLL, and others.

As demonstrated in Chapter 3, these methods will work fine within Ajax but are not supported

ubiquitously by client or server; readers are directed to the Web to read up on them.

HTTP Headers

Both HTTP requests and responses will contain headers. Regardless of type, headers follow

a format like:

Header-name : Header-value

where Header-name is the name of the particular header, such as User-Agent, and

Header-value is the corresponding value, such as Mozilla/5.0. The capture here shows

a few headers in a request:

NNOT EOTE As shown throughout the book, using an HTTP debugging tool will be quite useful. Browser-

hosted tools like Firebug (www.getfirebug.com) for Firefox or local proxy tools like Fiddler

(www.fiddlertool.com), which is browser agnostic are good places to start. If you’d like more choices,

visit http://ajaxref.com/resources.html for a list of useful JavaScript and Ajax tools and resources.

The HTTP 1.1 specification defines a number of different types of headers, including

custom or more appropriately extension headers. Table B-2 lists the types of headers and a

simple example of each.

Header Type Description Example

General header Exists in either request or

response

Date: Sun, 11 Aug 2001 13:24:52

GMT

Request header Specific to making a request Accept-Encoding: gzip,deflate

Response header Specifically found in responses ETag: "4135cda4"

Entity header Describes a resource or payload Content-Length: 1968

Extension header New headers often defined by

a developer

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TABLE B-2 HTTP Header Categories