Unit 1 Notes HTML PDF

Unit 1 Introduction To Web Web development refers to the creating, building, and maintaining of websites. It includes aspects such as web design, web publishing, web programming, and database management. It is the creation of an application that works over th...

Unit 1 Introduction To Web Web development refers to the creating, building, and maintaining of websites. It includes aspects such as web design, web publishing, web programming, and database management. It is the creation of an application that works over the internet i.e. websites. The word Web Development is made up of two words, that is:  Web: It refers to websites, web pages or anything that works over the internet.  Development: It refers to building the application from scratch. Web Development can be classified into two ways:  Frontend Development  Backend Development Frontend Development The part of a website where the user interacts directly is termed as front end. It is also referred to as the ‘client side’ of the application. Frontend Roadmap Frontend Development Roadmap Popular Frontend Technologies  HTML: HTML stands for HyperText Markup Language. It is used to design the front end portion of web pages using markup language. It acts as a skeleton for a website since it is used to make the structure of a website.  CSS: Cascading Style Sheets fondly referred to as CSS is a simply designed language intended to simplify the process of making web pages presentable. It is used to style our website.   JavaScript: JavaScript is a scripting language used to provide a dynamic behavior to our website.  Bootstrap: Bootstrap is a free and open-source tool collection for creating responsive websites and web applications. It is the most popular CSS framework for developing responsive, mobile- first websites. Backend Development Backend is the server side of a website. It is part of the website that users cannot see and interact with. It is the portion of software that does not come in direct contact with the users. It is used to store and arrange data. Backend Roadmap Backend Development Roadmap Popular Backend Technologies  PHP: PHP is a server-side scripting language designed specifically for web development.  Java: Java is one of the most popular and widely used programming languages. It is highly scalable.  Python: Python is a programming language that lets you work quickly and integrate systems more efficiently.  Node.js: Node.js is an open source and cross-platform runtime environment for executing JavaScript code outside a browser. Internet The Internet is the foremost important tool and the prominent resource that is being used by almost every person across the globe. It connects millions of computers, webpages, websites, and servers. Using the internet we can send emails, photos, videos, and messages to our loved ones. Or in other words, the Internet is a widespread interconnected network of computers and electronic devices(that support Internet). It creates a communication medium to share and get information online. Advantages of the Internet  Online Banking and Transaction: The Internet allows us to transfer money online through the net banking system. Money can be credited or debited from one account to the other.  Education, Online Jobs, Freelancing: Through the Internet, we are able to get more jobs via online platforms like Linkedin and to reach more job providers. Freelancing on the other hand has helped the youth to earn a side income and the best part is all this can be done via the INTERNET.  Entertainment: There are numerous options for entertainment online we can listen to music, play games can watch movies, and web series, and listen to podcasts, youtube itself is a hub of knowledge as well as entertainment.  New Job Roles: The Internet has given us access to social media, and digital products so we are having numerous new job opportunities like digital marketing and social media marketing online businesses are earning huge amounts of money just because the Internet is the medium to help us to do so.  Best Communication Medium: The communication barrier has been removed from the Internet. You can send messages via email, Whatsapp, and Facebook. Voice chatting and video conferencing are also available to help you to do important meetings online.  Comfort to humans: Without putting any physical effort you can do so many things like shopping online it can be anything from stationeries to clothes, books to personal items, etc. You can books train and plane tickets online.  GPS Tracking and google maps: Yet another advantage of the internet is that you are able to find any road in any direction, and areas with less traffic with the help of GPS on your mobile. Disadvantages of the Internet  Time Wastage: Wasting too much time on the internet surfing social media apps and doing nothing decreases your productivity rather than wasting time on scrolling social media apps one should utilize that time in doing something skillful and even more productive.  Bad Impacts on Health: Spending too much time on the internet causes bad impacts on your health physical body needs some outdoor games exercise and many more things. Looking at the screen for a longer duration causes serious impacts on the eyes.  Cyber Crimes: Cyber bullying, spam, viruses, hacking, and stealing data are some of the crimes which are on the verge these days. Your system which contains all the confidential data can be easily hacked by cybercriminals.  Effects on Children: Small children are heavily addicted to the Internet watching movies, and games all the time is not good for their overall personality as well as social development.  Bullying and Spreading Negativity: The Internet has given a free tool in the form of social media apps to all those people who always try to spread negativity with very revolting and shameful messages and try to bully each other which is wrong.  World Wide Web (WWW) The World Wide Web is a collection of all the web pages, and web documents that you can see on the Internet by searching their URLs (Uniform Resource Locator) on the Internet. For example, www.geeksforgeeks.org is the URL of the GFG website, and all the content of this site like webpages and all the web documents are stored on the world wide Web. The World Wide Web is an information retrieval service of the web. It provides users with a huge array of documents that are connected to each other by means of hypertext or hypermedia links. Here, hyperlinks are known as electronic connections that link the related data so that users can easily access the related information hypertext allows the user to pick a word or phrase from text, and using this keyword or word or phrase can access other documents that contain additional information related to that word or keyword or phrase. Internet Protocols Internet Protocols are a set of rules that governs the communication and exchange of data over the internet. Types of Internet Protocol Internet Protocols are of different types having different uses. These are mentioned below: TCP/IP(Transmission Control Protocol/ Internet Protocol) SMTP(Simple Mail Transfer Protocol) PPP(Point-to-Point Protocol) FTP (File Transfer Protocol) SFTP(Secure File Transfer Protocol) HTTP(Hyper Text Transfer Protocol) HTTPS(HyperText Transfer Protocol Secure) TELNET(Terminal Network) POP3(Post Office Protocol 3) IPv4 IPv6 ICMP UDP IMAP SSH Gopher 1. TCP/IP(Transmission Control Protocol/ Internet Protocol) These are a set of standard rules that allows different types of computers to communicate with each other. The IP protocol ensures that each computer that is connected to the Internet is having a specific serial number called the IP address. TCP specifies how data is exchanged over the internet and how it should be broken into IP packets. It also makes sure that the packets have information about the source of the message data, the destination of the message data, the sequence in which the message data should be re- assembled, and checks if the message has been sent correctly to the specific destination. The TCP is also known as a connection-oriented protocol. 2. SMTP(Simple Mail Transfer Protocol) These protocols are important for sending and distributing outgoing emails. This protocol uses the header of the mail to get the email id of the receiver and enters the mail into the queue of outgoing mail. And as soon as it delivers the mail to the receiving email id, it removes the email from the outgoing list. The message or the electronic mail may consider the text, video, image, etc. It helps in setting up some communication server rules. 3. PPP(Point-to-Point Protocol) It is a communication protocol that is used to create a direct connection between two communicating devices. This protocol defines the rules using which two devices will authenticate with each other and exchange information with each other. For example, A user connects his PC to the server of an Internet Service Provider and also uses PPP. Similarly, for connecting two routers for direct communication it uses PPP. 4. FTP (File Transfer Protocol) This protocol is used for transferring files from one system to the other. This works on a client-server model. When a machine requests for file transfer from another machine, the FTO sets up a connection between the two and authenticates each other using their ID and Password. And, the desired file transfer takes place between the machines. 5. SFTP(Secure File Transfer Protocol) SFTP which is also known as SSH FTP refers to File Transfer Protocol (FTP) over Secure Shell (SSH) as it encrypts both commands and data while in transmission. SFTP acts as an extension to SSH and encrypts files and data then sends them over a secure shell data stream. This protocol is used to remotely connect to other systems while executing commands from the command line. 6. HTTP(Hyper Text Transfer Protocol) This protocol is used to transfer hypertexts over the internet and it is defined by the www(world wide web) for information transfer. This protocol defines how the information needs to be formatted and transmitted. And, it also defines the various actions the web browsers should take in response to the calls made to access a particular web page. Whenever a user opens their web browser, the user will indirectly use HTTP as this is the protocol that is being used to share text, images, and other multimedia files on the World Wide Web. Note: Hypertext refers to the special format of the text that can contain links to other texts. 7. HTTPS(HyperText Transfer Protocol Secure) HTTPS is an extension of the Hypertext Transfer Protocol (HTTP). It is used for secure communication over a computer network with the SSL/TLS protocol for encryption and authentication. So, generally, a website has an HTTP protocol but if the website is such that it receives some sensitive information such as credit card details, debit card details, OTP, etc then it requires an SSL certificate installed to make the website more secure. So, before entering any sensitive information on a website, we should check if the link is HTTPS or not. If it is not HTTPS then it may not be secure enough to enter sensitive information. 8. TELNET(Terminal Network) TELNET is a standard TCP/IP protocol used for virtual terminal service given by ISO. This enables one local machine to connect with another. The computer which is being connected is called a remote computer and which is connecting is called the local computer. TELNET operation lets us display anything being performed on the remote computer in the local computer. This operates on the client/server principle. The local computer uses the telnet client program whereas the remote computer uses the telnet server program. 9. POP3(Post Office Protocol 3) POP3 stands for Post Office Protocol version 3. It has two Message Access Agents (MAAs) where one is client MAA (Message Access Agent) and another is server MAA(Message Access Agent) for accessing the messages from the mailbox. This protocol helps us to retrieve and manage emails from the mailbox on the receiver mail server to the receiver’s computer. This is implied between the receiver and the receiver mail server. It can also be called a one-way client-server protocol. The POP3 WORKS ON THE 2 PORTS I.E. PORT 110 AND PORT 995. 10. IPv4 The fourth and initially widely used version of the Internet Protocol is called IPv4 (Internet Protocol version 4). It is the most popular version of the Internet Protocol and is in charge of distributing data packets throughout the network. Maximum unique addresses for IPv4 are 4,294,967,296 (232), which are possible due to the use of 32-bit addresses. The network address and the host address are the two components of each address. The host address identifies a particular device within the network, whereas the network address identifies the network to which the host belongs. In the “dotted decimal” notation, which is the standard for IPv4 addresses, each octet (8 bits) of the address is represented by its decimal value and separated by a dot (e.g. 192.168.1.1). 11. IPv6 The most recent version of the Internet Protocol, IPv6, was created to address the IPv4 protocol’s drawbacks. A maximum of 4.3 billion unique addresses are possible with IPv4’s 32-bit addresses. Contrarily, IPv6 uses 128-bit addresses, which enable a significantly greater number of unique addresses. This is significant because IPv4 addresses were running out and there are an increasing number of devices that require internet access. Additionally, IPv6 offers enhanced security features like integrated authentication and encryption as well as better support for mobile devices. IPv6 support has spread among websites and internet service providers, and it is anticipated to gradually displace IPv4 as the main internet protocol. 12. ICMP ICMP (Internet Control Message Protocol) is a network protocol that is used to send error messages and operational information about network conditions. 13. UDP UDP (User Datagram Protocol) is a connectionless, unreliable transport layer protocol. Unlike TCP, it does not establish a reliable connection between devices before transmitting data, and it does not guarantee that data packets will be received in the order they were sent or that they will be received at all. Instead, UDP simply sends packets of data to a destination without any error checking or flow control. UDP is typically used for real-time applications such as streaming video and audio, online gaming, and VoIP (Voice over Internet Protocol) where a small amount of lost data is acceptable and low latency is important. UDP is faster than TCP because it has less overhead. It doesn’t need to establish a connection, so it can send data packets immediately. It also doesn’t need to wait for confirmation that the data was received before sending more, so it can transmit data at a higher rate. 14. IMAP IMAP (Internet Message Access Protocol) is a protocol used for retrieving emails from a mail server. It allows users to access and manage their emails on the server, rather than downloading them to a local device. This means that the user can access their emails from multiple devices and the emails will be synced across all devices. IMAP is more flexible than POP3 (Post Office Protocol version 3) as it allows  users to access and organize their emails on the server, and also allows multiple users to access the same mailbox. 15. SSH SSH (Secure Shell) is a protocol used for secure remote login and other secure network services. It provides a secure and encrypted way to remotely access and manage servers, network devices, and other computer systems. SSH uses public-key cryptography to authenticate the user and encrypt the data being transmitted, making it much more secure than traditional remote login protocols such as Telnet. SSH also allows for secure file transfers using the SCP (Secure Copy) and SFTP (Secure File Transfer Protocol) protocols. It is widely used in Unix-based operating systems and is also available for Windows. It is commonly used by system administrators, developers, and other technical users to remotely access and manage servers and other network devices. 16. Gopher Gopher is a type of file retrieval protocol that provides downloadable files with some description for easy management, retrieving, and searching of files. All the files are arranged on a remote computer in a stratified manner. It is an old protocol and it is not much used nowadays. Phases of Web Development Web Development refers to a term that includes all the processes involved in developing a web project or website. It contains the various phases such as planning, designing, testing, and launching of the web project. The various stages that are needed in order to develop a web project in web development are as following: Strategy: The first step in the web development process for a developer is to make a strategy for developing a web page or web site. In the strategy phase, web developer has to done the following:  Deciding goals and objectives  Developing team  Make the appropriate analysis associated with problem and review the analysis  Formulate a list of tasks  Proposal of project to web team for developing Design and Specification: After the strategy-making, the next step in the web development process is to develop a planned work. Web developer has to determine the schedule and the specifications. The tasks in this phase are as follows.  Developing approach  Planning of contents needed for use  Making of rough design for project  Making of final design from rough design, if there is no considerable modification in rough design.  Frame a prototype of project for developing  Test the prototype If prototype is accomplish, then go to next phase phase-3 otherwise repeat the phase 2 until prototype is accomplish. Production of desired result: In this phase of the web development process, the actual functional site is built. After the proper testing of the prototype, the developer has to work on developing the actual live web project. The actual live web project is built according to the requirements of the client. Web developer has to consider all the situations from the design phase to create all the features in the web project. This phase involves both front end development and back end development of the website. Testing and Maintenance: Testing is an important phase in the web development process. Testing is performed by the developers and testers to ensure the client’s requirements after completion of the web project. In this phase, quality assurance and browser compatibility issues of the website are checked. Testers test all the developed features and assure the validity of the written code. Various types of testing such as integration testing, regression testing, functional testing, smoke testing, load testing, and performance testing are performed in this phase by both testing and development teams. Testing can be performed manually or automatically on the basis of the type of testing and web projects. If desired and satisfactory results are not found, the proper actions for removing the bugs are taken. Registration with ISP: After completion of the Testing and Maintenance and removing all the bugs from the project, the next step or phase is to register the web project with the regional ISP to make the web project legal. The web project is delivered to the client after uploading the website to a server. File transfer protocol (FTP) is used to host the website to a hosting server. The client has to select and decide the ISP which provides domain name registration and web hosting services. After setup of these accounts and registering with the ISP so that the web project gets an accurate domain space at the ISP server. Launch: This is the last phase of the web development process. Project is launched after getting registered with ISP. after launching, web project is publicly accessed by the users of the particular domain. The tasks performed in the launch phase are as follows.  Migration of data  Launching of server  Merging of code  Redirecting domain name Fundamentals of Web Design: Web Design is a field related to designing websites on the Internet. Without a good design, a website fails to perform well and cannot produce a good impact on the user. Design is a creative process that affects the ranking of the brand. A good website design helps to create an engaging online presence that captivates the audience. Types of Web design The following are the types in which you can do Web Design: Static Website: This type of design is used when little or no interaction is required from the user. Dynamic Website: When user interaction is required and information is to be displayed according to the request then a dynamic design pattern is followed. E-commerce Website: This type of website design is required when a business wants to sell their products to the consumer. Flat Design: Minimalist approach characterized by clean, simple elements, vibrant colors, and absence of textures or gradients. Elements of Web Design While designing websites, one has to keep in mind both the appearance and functionality of websites. There are basically two elements of web design i.e., visual elements and functional elements.  1. Visual Elements: Visual elements simply mean an aspect or representation of something that we see. Types of visual elements include:  Layout  Shapes  Colors  Images and Icons 2. Functional Elements: Functional elements simply mean the aspect or representation of functionalities of websites. It simply represents what the website can do and how it works. Types of functional elements include  Navigation  User Interaction  Animation Applications of Web Design There is a wide range of applications that Web Design can be used for:-  Online representation for businesses in Corporate Websites.  Online stores for selling products/services in E-commerce Websites.  Platforms for sharing personal content in Blogs and Personal Websites.  Offering public services and information in Government and Nonprofit Websites.  Facilitating online reservations and bookings in Booking and Reservation Websites.  Providing information on specific topics or subjects in Informational Websites. Web Pages A webpage is a digital document that is linked to the World Wide Web and viewable by anyone connected to the internet having a web browser. It can contain any type of information, such as text, color, graphics, animations, videos, sounds, etc. A webpage is a document that is written in the HTML, it can be viewed from the Internet. It can be accessed by entering the URL on the address bar of the web browser. Components of a Webpage : Components of a webpage, Content wise Components of a webpage, Structure Wise ContentWise : Content-wise the components of a webpage are: Hypertext and Hyperlinks 1. Hypertext : It refers to a digital text, which is more than just text as it can include information in various media formats such as :  text  color  graphic  animation  video  sound  hyperlinks 2. Hyperlinks : It refers to a link from a hypertext file to another such file. A hyperlink can be in the form of a graphic or text, upon clicking where the linked document opens up. Structure Wise : Structure wise the components of a web page are : 1. Page Title – This is a single line text which is displayed on the title bar of the browser displaying web page. 2. Header – This is generally a one or two line text (sometimes a graphics/image) defining the purpose of the web page. It is displayed at the top of the web page, below the address bar of the browser. 3. Body of the Web page – This is the section below the header of the web page and it contains the actual content of the web page. 4. Navigational Links – These are the hyperlinks placed on the web page using which you can move the linked web pages/documents. 5. Footer – This is the bottom section of the web page. This is the section where usually the copyright notice, website contact information, etc. is put. Characteristics of a Web Page Following are some characteristics of a Web page: o A simple webpage can be created very quickly. o It takes very little time to create a webpage compared to a Website. o A web page and a website should be compatible with any device, such as Mobile, Desktop, Laptop, etc. o The search engine provides a web page through a link, and when a user clicks on that link, it is redirected to the webpage of a website. o A webpage can have any type of information including videos, and audios. o It can be made up of only HTML(Hypertext Markup Language), or CSS, or JavaScript for dynamic and attractive behavior. Types of Web Pages: Static Web pages: Static Web pages are very simple. It is written in languages such as HTML, JavaScript, CSS, etc. For static web pages when a server receives a request for a web page, then the server sends the response to the client without doing any additional process. And these web pages are seen through a web browser. In static web pages, Pages will remain the same until someone changes it manually. Dynamic Web Pages: Dynamic Web Pages are written in languages such as CGI, AJAX, ASP, ASP.NET, etc. In dynamic web pages, the Content of pages is different for different visitors. It takes more time to load than the static web page. Dynamic web pages are used where the information is changed frequently, for example, stock prices, weather information, etc.  Difference between Static and Dynamic Web Pages: SL.NO Static Web Page Dynamic Web Page In static web pages, Pages will remain In dynamic web pages, Content of pages are 1. same until someone changes it manually. different for different visitors. Static Web Pages are simple in terms of 2. Dynamic web pages are complicated. complexity. In static web pages, Information are change In dynamic web page, Information are change 3. rarely. frequently. Static Web Page takes less time for loading 4. Dynamic web page takes more time for loading. than dynamic web page. SL.NO Static Web Page Dynamic Web Page 5. In Static Web Pages, database is not used. In dynamic web pages, database is used. Static web pages are written in languages Dynamic web pages are written in languages 6. such as: HTML, JavaScript, CSS, etc. such as: CGI, AJAX, ASP, ASP.NET, etc. Static web pages does not contain any Dynamic web pages contains application 7. application program. program for different services. Static web pages require less work and cost Dynamic web pages require comparatively more 8. in designing them. work and cost in designing them. Difference between a Webpage and a Website Website Webpage Website is a collection of webpages It is part of website that includes information and displayed on the web with a client-like content and is displayed on the browser to user or browser. visitor. It contains more than one web webpages that It is a single document display on the browser. contain information. It is a combination of webpages created Information is usually written in HTML language. using HTML and CSS. It is a place used to display content. It is content displayed on the website. It requires more time to develop the website It requires less time to develop a webpage as compared as compared to webpages. to the website. It includes content or information about a single entity. It includes content about several entities.. Web Application: Web application is a piece of software that can be accessed by the browser. A Browser is an application that is used to browse the internet. Web application needs authentication. The web application uses a combination of server-side scripts and client-side scripts to present information. It requires a server to manage requests from the users. Example: Google Apps, Amazon, YouTube Client-Server Architecture Client-server architecture is a fundamental concept in system design where a network involves multiple clients and a server. Clients are devices or programs that request services or resources, while the server is a powerful machine providing these resources or services. This architecture allows efficient data management and resource sharing, making it popular in web applications, databases, and other network-based systems. By separating roles and distributing tasks, client-server architecture enhances performance, scalability, and security. Advantages of Client-Server Model  Centralized system with all data in a single place.  Cost efficient requires less maintenance cost and Data recovery is possible.  The capacity of the Client and Servers can be changed separately. Disadvantages of Client-Server Model  Clients are prone to viruses, Trojans, and worms if present in the Server or uploaded into the Server.  Servers are prone to Denial of Service (DOS) attacks.  Data packets may be spoofed or modified during transmission.  Phishing or capturing login credentials or other useful information of the user are common and MITM(Man in the Middle) attacks are common. URL (Uniform Resource Locator) A URL or Uniform Resource Locator is a Unique identifier that is contained by all the resources available on the internet. It can help to locate a particular resource due to its uniqueness. It is also known as the web address. A URL consists of different parts like protocol, domain name, etc. The users can access the URLs by simply typing them inside the address bar or by clicking any button or link web page. Example URL: https://www.geeksforgeeks.org/ Different Parts of a URL A URL consists of multiple parts that can helps you to visit a particular page on the internet. Every part of a URL has its own importance. Reference URL: https://www.geeksforgeeks.org/array-data-structure/?ref=home-articlecards#what-is-array The protocol or scheme: A URL starts with a protocol that is used to access the resource on the internet. The resource is accessed through the Domain Name System or DNS. There are multiple protocols available to use like HTTP, HTTPS, FTP, mailto, TELNET etc. The protocol used in the above URL is https. Domain or Host Name: It is the reference or name of the page that you are going to access on the internet. In this case, the domain name is: www.geeksforgeeks.org. Port Name: It is defined just after the domain name by using the colons between itself and the domain name. Generally, it is not visible in the URL. The domain name and the port name combinely can be known as Authority. The default port for web services is port80 (:80). Path: It refers to the path or location of a particular file or page stored on the web server to access the content of it. The path used here is: array-data-structure. Query: A query mainly found in the dynamic pages. It consists of a question mark(?) followed by the parameters. In above URL query is: ?. Parameters: These are the pieces of information inside a query string of URL. Multiple parameters can be passed to a URL by using the ampersand(&) symbol to separate them. The query parameter in above URL is: ref=home-articlecards. Fragments: The fragments appear at the end of a URL starts with a Hashtag(#) symbol. These are the internal page references that refers to a specific section within the page. The fragment in the above URL is: #what- is-array. IP Address An IP address is a unique address that is used to identify computers or nodes on the internet. This address is just a string of numbers written in a certain format. It is generally expressed in a set of numbers for example 192.155.12.1. Here each number in the set is from 0 to 255 range. Or we can say that a full IP address ranges from 0.0.0.0 to 255.255.255.255. And these IP addresses are assigned by IANA(known as Internet Corporation For Internet Assigned Numbers Authority). Types of IP Address IP Address is of two types: 1. IPv4 2. IPv6 1. IPv4: Internet Protocol version 4. It consists of 4 numbers separated by the dots. Each number can be from 0-255 in decimal numbers. But computers do not understand decimal numbers; they instead change them to binary numbers which are only 0 and 1. Therefore, in binary, this (0-255) range can be written as (00000000 – 11111111). Since each number N can be represented by a group of 8-digit binary digits. So, a whole IPv4 binary address can be represented by 32-bits of binary digits. In IPv4, a unique sequence of bits is assigned to a computer, so a total of (2^32) devices approximately = 4,294,967,296 can be assigned with IPv4. The IPv4 address is divided into two parts: Network ID and Host ID. IPv4 can be written as: 189.123.123.90 Classful IP addressing is a way of organizing and managing IP addresses, which are used to identify devices on a network. The 32-bit IP address is divided into five sub-classes. These are given below:  Class A  Class B  Class C  Class D  Class E Each of these classes has a valid range of IP addresses. Classes D and E are reserved for multicast and experimental purposes respectively. The order of bits in the first octet determines the classes of the IP address. The class of IP address is used to determine the bits used for network ID and host ID and the number of total networks and hosts possible in that particular class. Each ISP or network administrator assigns an IP address to each device that is connected to its network. 2. IPv6: There is a problem with the IPv4 address. With IPv4, we can connect only 4 billion devices uniquely, there are much more devices in the world to be connected to the internet. So, gradually we are making our way to IPv6 Address which is a 128-bit IP address. In human-friendly form, IPv6 is written as a group of 8 hexadecimal numbers separated with colons (:). But in the computer-friendly form, it can be written as 128 bits of 0s and 1s. Since, a unique sequence of binary digits is given to computers, smartphones, and other devices to be connected to the internet. So, via IPv6 a total of (2^128) devices can be assigned with unique addresses which are actually more than enough for upcoming future generations. IPv6 can be written as: 2011:0bd9:75c5:0000:0000:6b3e:0170:8394 Classification of IP Address An IP address is classified into the following types: 1. Public IP Address: This address is available publicly and it is assigned by your network provider to your router, which further divides it to your devices. Public IP Addresses are of two types,  Dynamic IP Address  Static IP Address: 2. Private IP Address: This is an internal address of your device which are not routed to the internet and no exchange of data can take place between a private address and the internet. 3. Shared IP addresses: Many websites use shared IP addresses where the traffic is not huge and very much controllable, they decide to rent it to other similar websites so to make it cost-friendly. Several companies and email sending servers use the same IP address (within a single mail server) to cut down the cost so that they could save for the time the server is idle. 4. Dedicated IP addresses: A dedicated IP Address is an address used by a single company or an individual which gives them certain benefits using a private Secure Sockets Layer (SSL) certificate which is not in the case of a shared IP address. It allows to access the website or log in via File Transfer Protocol (FTP) by IP address instead of its domain name. It increases the performance of the website when the traffic is high. DNS An application layer protocol defines how the application processes running on different systems; pass the messages to each other. o DNS stands for Domain Name System. o DNS is a directory service that provides a mapping between the name of a host on the network and its numerical address. o DNS is required for the functioning of the internet. o Each node in a tree has a domain name, and a full domain name is a sequence of symbols specified by dots. o DNS is a service that translates the domain name into IP addresses. This allows the users of networks to utilize user-friendly names when looking for other hosts instead of remembering the IP addresses. o For example, suppose the FTP site at EduSoft had an IP address of 132.147.165.50, most people would reach this site by specifying ftp.EduSoft.com. Therefore, the domain name is more reliable than IP address. Web Browser The web browser is an application software to explore www (World Wide Web). It provides an interface between the server and the client and it requests to the server for web documents and services. It works as a compiler to render HTML which is used to design a webpage. Whenever we search for anything on the internet, the browser loads a web page written in HTML, including text, links, images, and other items such as style sheets and JavaScript functions. Google Chrome, Microsoft Edge, Mozilla Firefox, and Safari are examples of web browsers. Difference between HTTP and HTTPS HTTP HTTPS HTTPS for HTTP stands HyperText for HyperText Transfer Transfer Protocol Protocol. Secure. In HTTP, URL In HTTPs, URL begins with starts with “http://”. “https://”. HTTPs uses HTTP uses port 443 port number 80 for number for communication. communication. HTTP is HTTPs is considered to considered as be unsecure. secure. HTTP works at HTTPS works Application at Transport Layer. Layer. In HTTP, Encryption is HTTP HTTPS Encryption is present in absent. HTTPS. HTTP does not HTTPS needs require any SSL certificates. Certificates. HTTP does not HTTPS helps to improve search improve search ranking ranking HTTP faster HTTPS slower than HTTPS than HTTP While HTTPS will have the HTTP does not data before use data sending it and hashtags to return it to its secure data. original state on the receiver side. In HTTP Data In HTTPS Data is transfer in transfer in plaintext. ciphertext. HTTP Should HTTPS Should be avoided. be preferred. Search engines Improved do not favour reputation of the insecure the website in website. search engine. HTTPS HTTP Does not Requires require SSL/TLS SSL/TLS or implementation Certificates with Certificates. In HTTPS In HTTP Users Users are ar worried confident about about their data. the security of their data. Absolute Path and Relative Path Absolute File Paths Absolute file paths specify the complete location of a file in a system, starting from the root directory. They include the full directory path, ensuring precise file identification regardless of the current directory location. Syntax Relative File Path A relative file path in HTML refers to the location of a file relative to the current web page’s location. Syntax