From OpenSCADAWiki
HTTP protocol is used to transfer the WWW content. For example, via HTTP the following types of documents are transmitted: html, xhtml, png, javascript, and many others. Support HTTP in OpenSCADA together with the transport Sockets and SSL allows to implement various user functions based on the WWW interface. The module initially implements two main methods of the HTTP protocol "GET", "POST", and currently any HTTP method. The module provides control of the integrity of HTTP-queries and, jointly with Sockets and SSL transport, allows to "collect" whole requests from their fragments, as well as hold of the connection "alive" (Keep-Alive).