Web Technologies.pptx
- 2. What is Web Technology? • Web technologies refers to the way computers/devices communicate. with each other using mark up languages. It is communication. across the web, and create, deliver or manage web content using hypertext markup language (HTML).
- 3. What Are Web Technologies? • Web technologies are the various tools and techniques that are utilised in the process of communication between different types of devices over the internet. • To understand this term in a better manner, let’s break it down into two pieces: ‘web’ and ‘technology’.
- 4. The web • The web, in this case, refers to the World Wide Web, more commonly known as WWW. It first came into being in 1989 when famous scientist and engineer, Tim Berners-Lee, came up with an efficient mechanism to share resources between scientists all over the world.
- 5. THE INTERNET AND WWW • The Internet is a global information network where the connected computers communicate with each other. With the Internet, you can search for information, communicate with other users, transfer files from one computer to another, download programs, pay your bills on an online banking system, etc. In this chapter, you will learn about the basics of the Internet, various online services and “netiquette,” i.e. how to behave online.
- 6. STRUCTURE AND ADDRESS PRACTICES ON THE INTERNET • The backbone of the global telecommunication network, the Internet, comprises servers connected to each other through high-speed data communications connections. Numerous local area networks (LANs) are connected to these servers. The LANs, for their part, offer individual users the possibility to connect to the Internet through different devices (computers, TVs, smartphones, etc.). • Your device, when it accesses the Internet, is assigned a so-called Internet address which identifies it. Without this address your device cannot connect to the Internet, but at the same time, it means that your movements in the Internet can be traced – often with a fair amount of detail. So, keep in mind that your activities in the Internet leave traces.
- 7. DOMAIN NAME SYSTEM – DNS • The networks and services in the Internet also have plain-language names, called domain names. The plain-language domain names, such as www.helsinki.fi, are assigned to the Internet addresses by the Domain Name System (DNS). Understanding the principles of this system will help you remember where different web services are located, since the domain name often consists of these parts:“service name”. “service domain”. “area code”. • moodle.helsinki.fi • flamma.helsinki.fi • wiki.helsinki.fi • maps.google.fi
- 8. • The networks and services in the Internet also have plain-language names, called domain names. The plain-language domain names, such as www.helsinki.fi, are assigned to the Internet addresses by the Domain Name System (DNS). Understanding the principles of this system will help you remember where different web services are located, since the domain name often consists of these parts:“service name”. “service domain”. “area code”. • moodle.helsinki.fi • flamma.helsinki.fi • wiki.helsinki.fi • maps.google.fi
- 9. THE IP ADDRESSES SYSTEM • DNS addresses – such as www.helsinki.fi – are important to you because they are easy to understand, but in reality most communication on the Internet is based on IP (Internet Protocol) addresses, which are long series of numbers (such as 193.166.3.1). IP addresses allow each computer connected to the Internet to be identified, enabling communication between different computers. • An example: if you want to look at the web pages of the Aalto University, your computer will find out the IP address associated with the www.aalto.fi server. After finding this information, your browser sends a request to Aalto’s IP address (104.17.222.22) for the front page of the www server. At this point, the Aalto server is informed that the request was sent by your computer, so the server will send the front page to your computer’s IP address.
- 10. ONLINE ETIQUETTE • On this page, you will find information about the Internet etiquette, or netiquette. The netiquette is a set of guidelines on how to behave online. If you ignore these guidelines, you can easily damage your online reputation. • Note that in addition to these general rules, various services such as e-mail lists, social media and the University of Helsinki have their own specific rules. • Be yourself: always log on to your services with your own username and password. In most services, the use of another person’s ID is prohibited, and identity theft is an act punishable by law. If you leave your computer, even for a short while, lock your workstation so that nobody can access the open services under your name. • Be polite when writing e-mails: when used correctly, e-mail is an effective means of communication. When sending email, you may be tempted to say something it that you will regret later. Do not write anything that you would not be willing to tell a person face to face. Do not send jokes or inappropriate messages to people you do not know personally.
- 11. • Respect the recipient’s inbox: do not burden the recipient’s inbox unnecessarily and do not forward chain letters. Before sending attachments, consider whether they are really necessary and whether the recipient will be able to open them. Your e-mail may be one of hundreds of messages in the recipient’s inbox, so do not expect an immediate answer. • Be considerate in online discussions: if you participate in discussions, be polite and do not disturb or offend others. Make sure that your message stays on topic. Disturbing or offensive users may be tracked down later, even if the discussion has been anonymous. In case of a problem, contact the site administration. • Take care of information security: Keep your passwords in a safe place where others cannot access them. Never divulge your passwords to other people! Make sure you do not send or reply to virus mail. If the message title or the name of an attachment looks suspicious, delete the message without opening it. • Know what you are agreeing to: there are services on the web that you have to register for. Read the sign-up instructions carefully and make sure you understand them before agreeing to anything. Do not say yes, unless you understand the question. • If a service requires registration and asks for your personal information, think carefully what information you want to disclose about yourself. Be especially careful in giving out your e-mail address to avoid becoming flooded by spam (junk mail). Also, be extra careful when sending credit card details online!
- 12. • Be critical: bear in mind that there is no publishing threshold on the Internet, so anybody can publish almost anything. Not all information found on websites is true or accurate. If an offer or service sounds too good to be true, it probably is. Particularly dubious are e-mail messages that advertise significant financial benefits or medicines that may be illegal in Finland or dangerous to the user. • The web has a long memory: do not forget that everything you write in an online discussion, e-mail message or on your own page can be read many years from now. • The law and the web: Everything that is illegal is illegal on the Internet as well. • The web has a long memory: do not forget that everything you write in an online discussion, e-mail message or on your own page can be read many years from now. • The law and the web: Everything that is illegal is illegal on the Internet as well. •
- 13. LAWS AND REGULATIONS • The Internet allows for unprecedented freedom of communication, but the freedom comes hand in hand with responsibility. For example, the author of a website is always responsible for the contents and legality of the site. • Libel and defamation: do not post online false information or insinuations about a person that could cause damage, suffering or contempt. In other words: do not publish online any defamatory material or anything that you would not be willing to express in any other context and be prepared to take the consequences. Also, do not post online any information, insinuation or image of a person that could cause damage, suffering, or contempt. • Copyright and trademark law: do not distribute on the Internet any material – such as music, text, photographs, drawings or trademarks – to which you do not own the rights. Unauthorized distribution and use of such material may lead to legal consequences.
- 14. • Confidentiality of communication: according to the constitution, every citizen has the right to privacy in their communication with others. The legislation also applies to e-mail and all electronic communications. Therefore, do not open e-mails addressed to other recipients without the express permission of the recipient! • Do not disrupt the operation of the data network: intentional disrupting or overloading of the data network, data transfer, e-mail and other online services is prohibited. • Hacking: intrusion into or unauthorized use of an information system – even if no damage occurs – is a criminal offence which in the worst case can lead to a jail sentence. The mere attempt of intrusion or unauthorized use is punishable. • Creating and spreading viruses: creating and deliberately spreading viruses are punishable offences.
- 15. • The concept of the web can easily be explained with the help of an example. • Let’s suppose you are looking for a picture of a cute llama. You type ‘www.google.com’ into your web browser. You enter ‘cute llama’ into the search bar and click on the ‘Images’ tab. Google gives you a plethora of llama pictures collected from millions of different sources. • After scrolling for a bit, you think, “Oh, I like this picture!” But you need to see the full-sized image before you download it. So, you open the original image and arrive at this page:
- 16. • Do not send e-mail advertising: do not use e-mail for marketing purposes unless you have permission from the recipients. It is illegal to send automated mass mail to individual persons. However, sending information to companies, your clients or friends is allowed. Even in these cases you should remove the recipient’s name from the distribution list if they so request. You can make the recipients’ names invisible to others by entering them in the bcc (Blind Carbon Copy) box. • Keeping a register of persons: if you collect personal information from the web or people visiting your home page (e.g. by asking them to register), you must comply with the provisions of the Personal Data Act. • Child pornography: distribution and possession of child pornography is illegal regardless of the format of the material. • Racism: racism and incitement to racism is prohibited.
- 18. • Notice the red box? • That is the URL (a type of identifier) for this particular image. In the same way, every llama picture you viewed would have a different URL that would help locate that image on the internet. • All these webpages, documents, and any other resources are identified and located with the help of their URLs. These collectively form what we refer to as the World Wide Web. • The knowledge that you accumulate about the web and how it works needs to be applied in order to make better sense of it. For this, you need to know the basics of some common web technologies. • “What is web technology and what is the web?” In order to gain a better understanding of the web, let’s take a look at some basic types and examples of web technology that are commonly used in this field.
- 19. Technology • Technology is the application of scientific knowledge to the practical aims of human life or, as it is sometimes phrased, to the change and manipulation of the human environment.
- 20. What Are The Different Types Of Web Technologies? • Since we have a limited space to examine the wide array of web technologies available, we have picked a few that are used most often by both beginners and experts in the industry. We have divided them into the following sections: 1. The basics, which will cover web browsers and some web app development fundamentals 2. Programming languages and frameworks which are used in the development of websites 3. Databases that are used at the backend to store data required or collected by websites 4. Some protocols, that is, rules for communicating on the web 5. Graphic, audiovisual, and other multimedia elements 6. Some data formats that are usually used to transmit data over the internet 7. Other miscellaneous web technologies
- 21. The Basics • This is one of the most crucial parts of our introduction to web technologies. In this section, we will talk about web browsers and some other web fundamentals.
- 22. Web Browsers • Web browsers, often just called browsers, make it possible for us to view all the resources that are part of the World Wide Web. They are based on a client-server architecture. The client is the browser in this scenario. You can think of the server as a combination of software and hardware that receives the client’s requests and then sends the requested resource to the client.
- 24. INTRODUCTION TO THE USE OF BROWSERS • This page covers the following topics about web browsers: • Different web browsers • URL, browsing basics, and problem solving • Use of new browser windows and tabs • Saving and copying information from browser • Web browsers are very versatile tools because in addition to browsing the Internet, they can be used for many other things as well, like watching videos, listening to online radio stations and managing e- mail.
- 25. • If problems occur, you might want to try using another browser, or update your browser. In any case, it is good a idea to update the browser from time to time. Browsers will be improved as new technologies emerge and security holes are revealed, so using up-to- date versions is highly recommended!
- 26. DIFFERENT BROWSER PROGRAMS • Examples of popular, easy-to-use, and free browsers include Mozilla Firefox and Opera. Older Windows operating systems include a browser called Internet Explorer. The browser included in Windows 10 is called Edge. Macs come pre-installed with a browser called Safari. The different browsers look very similar, and they work almost identically.
- 27. BROWSING WEB PAGES • If you know the URL of the page you want, type it into the address bar and click on the Enter, Go or other similar button on the browser.
- 28. • Following is a list of things that are useful to know about browser use. • You can move up and down on a page by using the scroll bar on the right or by using the mouse wheel. • Text that appears blue is usually a hyperlink, and clicking it will take you to the page in question. Note that pictures can contain links too, and that the link text will usually change its colour as soon as you have clicked it once. • The browser’s toolbar contains buttons which allow you to move from one page to another. Unless you have changed your browser settings, any pages you visit will be saved in the browser’s memory. You can use the navigation buttons to move between pages you have visited. You can usually return to the previous page by clicking the arrow pointing left and move forward by clicking the arrow pointing right. Most browsers will allow you to open a list using these buttons, which lets you to move further back/forward in your browser history. You can open the list by right-clicking the navigation button. • Most browsers do not have an actual menu bar. For example, in Firefox and Chrome, the most important functions can be found behind the menu button in the top right corner. In these browsers, the menu icon is symbolised by three stacked lines or dots.
- 29. URL ERRORS Normally, the browser will display the page you have requested, but sometimes you may receive an error message that says “Page cannot be found” or “404 File not found”. The reason is usually one of the following. • You have typed the address incorrectly: check the address, especially for upper-case letters and special characters. • The online service you wanted is temporarily or permanently out of use: use a search engine to find out if the information is available elsewhere on the Web. • The page you wanted has been moved or renamed: try shortening the URL or use the online service’s own search field.
- 30. • Upper and lower case letters are often significant in Internet addresses: the address http://www.helsinki.fi/Talo points to a different page than http://www.helsinki.fi/talo, so pay attention; if you cannot access a page, the reason may be that you have used the wrong case in the address.
- 31. USING SEVERAL BROWSER WINDOWS • In nearly all browsers, you can have several browser windows open at the same time. You can open a new browser window in either of the following ways: • go to the File menu in the browser and select New Window or • press CTRL+N on the keyboard. • These methods usually open the start page of the browser in the new window. If you want to open a link on a webpage in a new browser window, right-click the link. This will bring up a pop-up menu where you can select Open Link in New Window. •
- 33. USING TABS • You can also open webpages on separate tabs in the same browser window. When you use tabs, you can see the titles of all open pages in one and the same browser window and you can easily navigate between them. • You can open a new tab as follows: • click on the + symbol to the right of the tabs, or • press CTRL+T on the keyboard. • The image below shows three tabs, with the tab Unisport displayed.
- 34. • You can also open links in new tabs: Right-click on the link and, in the pop-up menu, select Open Link in New Tab (see the image above showing how to open a new window).
- 35. SAVING AND COPYING INFORMATION FROM BROWSER • If you want, you can copy and save information (images, text) from a webpage for later use. The Copyright Act protects texts, photographs, sound recordings and other works so that material copied from the Internet normally cannot be used without the copyright owner’s permission (more on copyright).
- 36. COPYING TEXT • You can copy text from a website into another application via the clipboard, just like in any other program . • Note that when you copy-paste a text from the Web, the formatting of the webpage usually comes with the text. If you want to paste the text without the formatting, choose Paste Special instead of Paste, and then choose Unformatted text from the menu window that opens. Alternatively, you can drop all formatting by passing the text through a simple text editor (such as Windows Notepad) which will lose the formatting. Paste the copied text into the text editor, re-copy in the text editor and, finally, paste into the target application. This method of getting rid of unnecessary formatting applies to other programs as well.
- 37. COPYING AND SAVING IMAGES • You can copy an image from a webpage to another application via the clipboard or save it to your own computer as follows: • Copying: place the mouse pointer on the image and right-click. In the pop-up menu that opens, select Copy Image. The image is copied to the clipboard, from where you can paste the image into other programs. • Saving: place the mouse pointer on the image and right-click. In the pop-up menu that opens, select Save Image As, and specify where you want to save the image. The image will be saved as a file to the location you specified.
- 39. OPENING AND SAVING LINKED FILES • To open files stored on a page, click the link and select Open from the window that opens. • Alternatively, you can save the file directly to your computer. In this way, you can open and read it later without an Internet connection. • In most browsers, you can save a file as follows. Right-click a hyperlink on a webpage. This will open a context menu in the browser. Select Save Link As (see the image below). You will be shown a window where you can select the folder to save the file to, as well as the name for the file. Finally, click Save.