REQUEST_METHOD = GET
Authoring/maintainance: HTTP extensions for this
HTTP/1.0 only defined the GET, HEAD and POST methods and for ordinary browsing this is enough. However, one may want to use HTTP to edit and maintain files directly on the server, instead of having to go through an FTP server as is common today. HTTP/1.1 adds a number of new methods for this.
PUT uploads a new resource (file) to the server under the given URL. Exactly what happens on the server is not defined by the HTTP/1.1 spec, but authoring programs like Netscape Composer use PUT to upload a file to the web server and store it there. PUT requests should not be cached.
Well, it's obvious, isn't it? The DELETE method requests the server to delete the resource identified by the URL. On UNIX systems this can fail if the server is not allowed to delete the file by the file system.