Important Terms Related to WWW
Client
A client is the computer hardware or software that receives a service made available by a server as part of the client–server model of computer networks. Any work done on the local client is known as client-side.
Web Page
A web page (or webpage) is a hypertext document provided by a web server as a response for the request from the client and displayed to the client in a web browser. A web page contains text or other files such as images written in the Hypertext Markup Language (HTML).
Static Web Page: A static web page (sometimes called a stationary page) is a web page that is delivered to the user’s web browser exactly as stored in the server.
Dynamic Web Page: A dynamic page delivers different content for different users while retaining the same layout and design. Such a page may take more time to load than a simple static page because server-side scripting language processes the page and it takes data from a database or reads a file.
Web Browser
A web browser (commonly referred to as a browser or internet browser) is an application software for accessing the World Wide Web (WWW). Web browser interprets the web pages and shows them in human readable format. Examples for web browsers are Google Chrome, Mozilla Firefox, Microsoft Edge and Apple Safari.
IP Address
An IP address is a set of numbers separated by periods. It is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication. Internet Protocol version 4 (IPv4) defines an IP address as a 32-bit number. IPv4 addresses are expressed like 192.168.1.2. Each number in the set can range from 0 to 255. So, the full IP addressing range starts from 0.0.0.0 to 255.255.255.255. However, because of the growth of the Internet and the exhaustion of available IPv4 addresses, a new version of IP (IPv6) is introduced which uses 128 bits for the IP address.
Uniform Resource Locator (URL)
URL (known as web address) is the mechanism used by browsers to retrieve any published resource on the web. URL uniquely identifies a web document, like web page, image or video, over the internet.
Eg: https://beginwebprogramming.com/web/
Here ‘https’ is known as ‘scheme’, “beginwebprogramming.com” is known as ‘domain name’ and a ‘port number’ like Port 80. Under normal circumstances we never use the port number. There are two kinds of URLs namely “Absolute URL” and “Relative URL”. An absolute URL is the one that contains the entire address of the page. A relative URL doesn’t contain any protocol or machine information. Its path generally refers to a resource on the same machine as the current document. Relative URLs are resolved to full URLs using a base URL.
Domain Name System (DNS)
DNS is the address book of the internet. Users type domain names on web browsers, not their Internet Protocol (IP) addresses. Each device connected to the Internet has a unique IP address which other machines use to find the device. DNS servers eliminate the need for humans to memorize IP addresses such as 192.168.1.2 (in IPv4), or more complex alphanumeric IP addresses. DNS resolves the typed domain name into corresponding IP address so that the browser can communicate with the intended device over the internet.
Web Server
A server is a computer that stores and delivers web content. The basic objective of the web server is to store, process and deliver web pages to the requested clients. The servers communicate with browsers using Hypertext Transfer Protocol (HTTP).
How does the web server work?
Web server receives the HTTP request from the client and responds to the client request in either of the following two ways:
- Sending the exact file to the client browser associated with the requested URL.
- Providing the result after invoking a script, written in server side scripting language, and communicating with the database such as MySQL.
The most used servers are Apache HTTP Server, Nginx Server, Internet Information Services (IIS), Lighttpd, Sun Java System Web Server and Jigsaw Server.
Internet Service Providers (ISPs)
Internet service providers (ISPs) are companies that provide web access to both businesses and individual users.ISPs provide Internet access, using a range of technologies to connect users to their network. Available technologies have ranged from computer modems to telephone lines, television cables, Wi-Fi, and fiber optics.
Server Side Scripting
Server side scripting is basically employed to create dynamic pages using a programming language in the web server. It can also access the file system residing at the web server. Some common server-side languages include PHP, Python and Java. Source code is not visible to the user because it’s output on the server side is an HTML page. The main advantage of a server side language is its ability to customize response, requirements and access rights based on the user.
Client Side Scripting
Client-side scripting means running scripts, such as JavaScript, on the client device, usually within a browser. Source code is visible to users since it runs on the client side. Client side scripting makes faster and more interactive web pages. Version of the browser is important in the client side scripting context since some of the old browsers may not support the latest technologies in JavaScript and CSS.