Web Development Basics

First, the HTML

1.html==hypertext Markup Language

2. Returned by the server, rendered by the browser

Web applications are typically made up of clients and servers

For us this client is the browser (Chrome, Firefox, etc.)

This server is the HTTP server (Apache, tomcat, etc.)

An HTML code that can be an HTML file stored on an HTTP server

It can also be dynamically generated and returned to the client through a dynamic scripting language such as PHP, ASP, and JSP.

When the browser receives the response from the HTTP server, it will parse and render the received HTML code.

Then presented to the user

Second, Uri/url/urn

1.url==uniform Resource Locator (Uniform Resource Locator)

Uniform Resource Locator represents the address information for a resource

Every file on the Internet has a unique URL

It contains information that indicates the location of the file and how the browser should handle it

Format of the URL:< protocol >//< host >:< port >/< path >

2.urn==uniform Resource Name (Uniform Resource name)

Represents a unique name for each resource

3.uri==uniform Resource Identifier (Uniform Resource Identifier)

is a string that identifies an Internet resource

The last occurrence relative to the URL and Urn,uri

are standard institutions such as the universal, in order to unify the criteria for resource positioning to develop a URI

URLs and urns become a subset of URIs.

But because many people are accustomed to using URLs, URLs are still used very extensively.

Iii. Introduction to the HTTP protocol

1.http==hypertext Transfer Protocol (Hypertext Transfer Protocol)

It is one of the most widely used network protocols on the Internet.

The intent of the HTTP protocol was designed to provide a way to publish and receive HTML pages

A resource requested through the HTTP protocol, identified by a URI

The HTTP protocol was introduced in 1990

After several years of use and development has been the continuous improvement and development

Iv. features of the HTTP protocol

1. Support client/server mode (one request and one response)

2. Flexible

HTTP protocol allows any type of data object to be transmitted

3. No connection

The meaning of no connection is to limit the processing of only one request per connection

The server disconnects after the client's request is processed and the customer's response is received

This way, the transmission time can be saved

4. No status

The HTTP protocol is a stateless protocol

Stateless means that the protocol has no memory ability to handle transactions

A lack of state means that if the previous information is required for subsequent processing, it must be re-transmitted

This may result in an increase in the amount of data transferred per connection

On the other hand, it responds faster when the server does not need the previous information

V. Methods of HTTP

Method name	Correspondence specification
GET	Make a request to a specific resource
POST	Submit data to a specified resource for processing requests

Vi. evolution of the HTTP protocol

	Finalization time	Description
HTTP0.9	1991	Prototype version, many defects
HTTP1.0	1996	First widely used version
HTTP1.1	1999	Version currently in use
Http-ng	1998	Not yet available for promotion

Web Development Basics