World Wide Web: Tutorial

Boolean Search Strategies

You can also use Boolean search strategies, adopted from Boolean algebra, to make your search more specific. Boolean algebra uses words such as AND, OR, and NOT, which programmers call logical operators. These operators narrow down or widen the search results. The AND operator allows you to narrow down the search results. For example, let's say that you are searching for the relationship between two concepts, such as music and learning. You could use the AND operator to search for "music AND learning." The search engine will then pick up sources related to both keywords, and not sources related to just one. The first Venn diagram in the image illustrates this concept. The OR operator enables you to widen the search parameters. For example, if you want your search results to include pages that mention either asteroids or comets, or both, then you would search for "asteroids OR comets." The search engine would pull up all of the sources that mention either one of the keywords, or both of them. The second Venn diagram illustrates this possibility. The NOT operator eliminates a particular word from the search. For example, you may want to search for "software" but would like to exclude any search result that includes mobile software. Search for "software NOT mobile." The final Venn diagram illustrates this type of search.

File Operations:

You can perform various file operations over the Internet to download or transfer files, or to compress data.

Hypertext

enabled programmers to create the World Wide Web.

Which type of icon is used to indicate the back button?

functional icon

Scroll bar:

is a bar on the right and the bottom of your screen. Dragging these bars moves the display of the page on the screen.

To understand how the WWW works, you need to study its components:

-web hardware and software -a hypertext markup language (HTML) that programmers use to code web pages -the HTTP protocol that web pages use -the URL (the website address).

HTML:

HyperText Markup Language, or HTML, is a language you can use to write code for web pages. The objective of this language is to identify and describe the various components of a web page.

Menu bar:

The menu bar displays various options, which perform different tasks. Let's look at these options. File: File allows you to open a saved document, save a page from the web, print a document, or email it. Edit: Edit allows you to cut, copy, and paste text from a web page. View: View allows you to customize your display screen, go back or forward, view the HTML source code, and so on. Bookmarks: The Bookmarks tab allows you to add and organize URLs that is used often. Tools: Tools allow you to set the security level for your computer, clearing your browser history, blocking pop-ups, and so on. Help: Help gives you an index for help on various topics related to the browser.

Minimize, Maximize, Close buttons:

These buttons make your browser window smaller or larger, or they close the browser completely.

Web directories:

This is a set of links to Internet resources, which individuals usually submit. Yahoo! Directory and the Open Directory Project are examples of web directories.

Natural-language search engine:

This tool enables users to search for information using natural language queries—for example, "What is a search engine?" This tool filters data based on context. Ask Jeeves is an example of a natural-language search engine.

Specialized search engine:

This tool focuses on a specific subject. For example, MapQuest and Google Maps are specialized search engines that provide geographical information.

Web crawler:

This tool is a database of Internet resources that a crawler program compiles. Google, Lycos, and Bing are some of the popular crawlers.

File download and transfer:

You can download and transfer files over the Internet through the File Transfer Protocol (FTP) between computers on a network. FTP uses the Transmission Control Protocol/Internet Protocol (TCP/IP) to exchange files. You can use FTP to send large files without access to an email system. FTP enables you to transfer files (text or images) securely.

Configuring Browser Settings

You need a web browser to access websites. Web browsing can be an enriching experience. It enables you to select what you like from the vast information available on the Web. However, it can also become a threat to you and your computer at times. Many websites look genuine but can install unwanted software (malware) on your computer that can steal your personal information. Some websites contain scripting languages (such as JavaScript) that automatically run on your browser. JavaScript has the potential to run malicious code when you open your browser. Therefore, you should always be aware of the functionality and features of your web browser. You can avoid these situations by managing the settings in your browser.

the Web:

a collection of info that people share over the Internet. -people access stored info on the Web using hyperlinks in text docs (web pages).

hyperlink:

a link to another web page. Users can navigate from one web page to another with hyperlinks.

HTTP:

a protocol (a predefined rule) that websites use to exchange information. Other online activities (such as email and chat) require a different set of protocols. For example, emails use the Simple Mail Transfer Protocol (SMTP). Chats use the Extensible Messaging and Presence Protocol (XMPP).

Tital bar:

displays the title of the web page that is on your screen.

Meta-Perch engine:

This tool queries multiple search engines and databases to generate search results. Metacrawler and Dogpile are examples.

Web hardware and software:

To access websites, you need to have the appropriate hardware and software. The hardware includes a desktop (or laptop) computer, an Internet connection, a modem, and a Local Area Network (LAN) card. Once you connect to the Internet, you'll need to use a web browser. A web browser is a software application that allows you to view web pages. Some of the popular web browsers include Microsoft Internet Explorer, Google Chrome, Mozilla Firefox, and Apple Safari.

Functional icons:

These buttons allow you to perform tasks within a browser, such as refreshing the screen, going back or forward to navigate through web pages, and so on.

Here are some steps to configure your browser settings. The steps may vary slightly on different browsers.

-Go to the Settings option in your web browser and select the option to clear your browsing history when you close the browser. This act will ensure that the browser will clear the history of websites that you have visited. -Check the Disable JavaScript option in the Settings options. -Select the option to block pop-up advertisements in your browser. Often, pop-up advertisements contain links that may download malicious software. -Select the option to automatically download your browser software whenever a new update is available. This act will ensure that you use only the latest browser software, with the latest security updates. -Disable automatic completion of sensitive information such as usernames and passwords on your browser. This act will ensure that the browser will not save your personal data. -Disable the option to track your location on your web browser. -Select the option for malware protection. When you do this, the browser will warn you when you try to access a website that contains malware. -Select the option to delete cookies (text files that store your preferences) in your browser when you close it. Also select the option to disable cookies from other websites. This act will ensure that your preferences are not shown as advertisements on web pages.

Features of a Good URL A URL enables a user to locate your website. Therefore, it is important that you create effective URLs. Let's consider some useful indicators for an effective URL.

-Your URL should indicate what your web page contains. For example, if you create a random name, such as www.k12examinations.edu/abc.html, a visitor will not be able to determine what the web page is about from the name abc.html. -Your website URL should not be too long. Separate the individual words in your URL with hyphens. This act will help visitors read and understand the name easily. For example: www.k12examinations.edu/writingURL/ how-to-write-a-URL. -An effective URL also enables the process of search engine optimization. It will anticipate the likely search words that a person might use. Search engine optimization ensures that your website show up near the top of the person's search results page.

The World Wide Web and Its Components: invented in the 1980s.

-waas a time when the demand to communicate and share info among users connected to the Internet reached a peak. -Tim Berners-Lee of the European Organization for Nuclear Research (CERN) built the ENQUIRE database system. This database had a rule that: whenever someone created a new page, the page had to link to an existing page. This rule gave rise to the concept of hypertext docs.

Search Strategies

A search engine is a powerful tool that allows you to find information on the Web. You can enter keywords in a search engine and get relevant results. If you enter a phrase in a search engine, each word is an individual keyword. If you want the search engine to filter data based on the entire phrase (and not individual words), you can enter the phrase in quotation marks. Let's say that you enter the phrase World Wide Web in quotation marks ("World Wide Web"). The search engine will search for the entire phrase instead of treating the words world, wide, and web as three separate words. Search engines usually ignore prepositions and conjunctions such as this, that, and which because they do not consider them to be keywords. However, if these words are in quotation marks or precede them with a plus sign (+), you tell the search engine to add them to the search. To exclude a particular word from a search, you should add a minus sign (-) before the word. For example, you want to search for pets, including cats and dogs, but excluding fish. You can do so with the help of the advanced search option of a search engine. The search results will appear in the format "pets + cats + dogs - fish." Some of the popular search engines are Google, Bing, and Yahoo.

more parts of the URL:

Domain name: A domain name tells you the type of organization that the website belongs to. For example, a .com domain name means that the website reflects commercial or business objectives, .edu is for educational objectives, and .net is a service provider's domain. In the example, .gov refers to a government website (such as NASA). You can also have a combination of domain names, such as .gov.uk. This combination indicates a UK government website. Resource ID: The resource ID is where your file resides on a web server. It is similar to the directory structure a computer uses, and it contains a path and a file name. In the example, the resource ID is audience/forstudents/careers/earth-profiles/index.html. This means that the index.html page resides in the earth-profiles folder.

File Compression:

File transfer can take up a lot of time, especially if your Internet connection is slow. The transfer of large files can also take up a large bandwidth. This makes it difficult for you to access other websites during the file transfer. File compression reduces the size of your files so that they can transfer faster. File compression techniques include algorithms that can often reduce your file size by more than half. When you compress a file, you— -remove unwanted text, images, and videos -compress repeated strings of data (for example, "BBBBBMM" compresses as "5B2M") Most organizations use a variety of algorithms and techniques to maximize file compression. A common file compression application is gzip.

Which protocol does the WWW use for communication?

HTTP

Parts of a URL Ex: http://www.nasa.gov/audience/forstudents/careers/earth- profiles/index.html

Protocol: Every URL starts with a protocol. The URL above starts with the HTTP protocol, which browsers use to access the web page. Sometimes the protocol is not visible in the URL; in such cases, you can assume that it is HTTP (http://). www: The letters www in the URL indicate that your page or website is on the World Wide Web. Server name: The server name tells you the name of the server that hosts the website. In the example above, the server name is nasa. This name declares that the web page is on the National Aeronautics and Space Administration (NASA) server.

Graphical User Interface (GUI) browser:

is a computer interface used to access the Internet. This interface uses windows, icons, menus, and so on to browse the Internet. When you open a GUI browser, you see a set of features that define the tasks of web browsing. Some popular GUI browsers include Internet Explorer, Mozilla Firefox, and Google Chrome. Every GUI browser has a different look and feel, but they all perform similar functions. Let's look at the example of Mozilla Firefox to learn about the parts of a GUI browser in detail.

URL:

is the address you enter in the browser's web address area to view a website. Every web page has a different URL.

Address field:

is the area where you enter the URL or the address of the website.

Which action does file compression perform?

removes unwanted text, images, and videos