What protocols support distributed computing on the web?

Several protocols support distributed computing on the web, including HTTP, SOAP, REST, XML-RPC, and JSON-RPC.

HTTP, or Hypertext Transfer Protocol, is the foundation of any data exchange on the web and it's a protocol used for transmitting hypertext requests and information between servers and browsers. It's stateless, meaning each command is executed separately, without any knowledge of the commands that came before it. This makes it a useful protocol for distributed computing as it allows for a scalable system.

SOAP, or Simple Object Access Protocol, is a messaging protocol that allows programs running on disparate operating systems to communicate with each other. It uses XML for its message format, which is language-independent, so it can be used with any programming language that can parse XML. SOAP is a versatile and robust protocol that can be used over a variety of protocols such as HTTP, SMTP, TCP, or even over a Message Queue.

REST, or Representational State Transfer, is an architectural style for providing standards between computer systems on the web, making it easier for systems to communicate with each other. REST-compliant systems, often called RESTful systems, are characterised by how they are stateless and separate the concerns of client and server. In REST, the client and server are able to evolve separately without depending on each other.

XML-RPC is a remote procedure call (RPC) protocol which uses XML to encode its calls and HTTP as a transport mechanism. It's a simple protocol that allows software running on disparate operating systems running on different environments to make procedure calls over the Internet. It's designed to be as simple as possible, while allowing complex data structures to be transmitted, processed and returned.

JSON-RPC is a remote procedure call protocol encoded in JSON. It's a light-weight, data-interchange format that's easy for humans to read and write, and easy for machines to parse and generate. It's a very simple protocol, defining only a few data types and commands, and the rest being left up to the application.

These protocols all support distributed computing on the web by providing a means for computers to communicate and share resources, regardless of their geographical location or the specific technologies used within each system.