Step1: The Client sends a Request¶

Every conversation on the web starts with a request. The request is a text message created by a client (e.g. a browser, an iPhone app, etc) in a special format known as HTTP. The client sends that request to a server, and then waits for the response.
Take a look at the first part of the interaction (the request) between a browser and the xkcd web server:
n HTTP-speak, this HTTP request would actually look something like this:

1 2 3 4

GET / HTTP/1.1 Host: xkcd.com Accept: text/html User-Agent: Mozilla/5.0 (Macintosh)

This simple message communicates everything necessary about exactly which resource the client is requesting. The first line of an HTTP request is the most important and contains two things: the URI and the HTTP method.
The URI (e.g. /, /contact, etc) is the unique address or location that identifies the resource the client wants. The HTTP method (e.g. GET) defines what you want to do with the resource. The HTTP methods are the verbs of the request and define the few common ways that you can act upon the resource:resource:

GET	Retrieve the resource from the server
POST	Create a resource on the serverIn addition to the first line, an HTTP request invariably contains other lines of information called request headers. The headers can supply a wide range of information such as the requested Host, the response formats the client accepts (Accept) and the application the client is using to make the request (User-Agent). Many other headers exist and can be found on Wikipedia's List of HTTP header fields article.
PUT	Update the resource on the server
DELETE	Delete the resource from the server

With this in mind, you can imagine what an HTTP request might look like to delete a specific blog entry, for example:

1	DELETE /blog/15 HTTP/1.1

There are actually nine HTTP methods defined by the HTTP specification, but many of them are not widely used or supported. In reality, many modern browsers don't support the PUT and DELETE methods.