Navigating the Web



Navigating the WebSince so many people create web pages, the Web should be chaotic. However, underlying systems are in place specifying how pages are organized on the Web and how they are delivered to your computer. This system involves unique addresses used to access each web page, a unique address for each computer, and browser features for locating and retrieving online content.IPs and URLsAn Internet Protocol (IP) address is a series of numbers that uniquely identifies a location on the Internet. An IP address consists of four groups of numbers separated by periods. For example: 225.73.110.102. A nonprofit organization called ICANN keeps track of IP numbers around the world.Because numbers would be difficult to remember for retrieving pages, we use a text-based address referred to as a uniform resource locator (URL) to go to a website. A URL, also called a web address, has several parts separated by a colon (:), slashes (/), and dots (.). The first part of a URL is called a protocol and identifies a certain way for interpreting computer information in the transmission process. Http, which stands for hypertext transfer protocol, and ftp, for file transfer protocol, are examples of protocols. Some sites use a secondary identifier for the type of site being contacted, such as www for World Wide Web site, but this is often optional.The next part of the URL is the domain name, which identifies the group of servers (the domain) to which the site belongs and the particular company or organization name. A suffix, such as .com or .edu, further identifies the domain. For example, the .com in the URL is a top-level domain (TLD). Several TLDs exists such as .com, .net, .org, .edu, and .gov. Table A provides a rundown of TLDs being used today.SuffixType of business siteBillboard: .comcompany or commercial institutionIntel: .edueducational institutionHarvard University: .govgovernment siteInternal Revenue Service: .intinternational organizations endorsed by treatyWorld Health Organization: siteU.S. Department of Defense: site for ISPsEarthlink: .orgnonprofit or private organizationRed Cross: Browsing Web PagesYou may already be quite comfortable with browsing the Internet, but you may not have pondered how browsers move around the Web and retrieve data. Any element of a web page (text, graphic, audio, or video) can be linked to another page using a hyperlink. A hyperlink describes a destination within a web document and can be inserted in text or a graphical object such as a company logo. Text that is linked is called hypertext.A website is a series of related web pages that are linked together. You get to a website by entering the URL, such as , in your browser. Every website has a starting page, called the home page, which is displayed when you enter the site URL. You can also enter a URL to jump to a specific page on a site, such as the Video-On-Demand page at Amazon’s site, Video-On-Demand.Searching the WebA search engine, such as , , and , catalogs and indexes web pages for you. A type of search engine, called a search directory, can also catalog pages into topics such as finance, health, news, shopping, and so on. Search engines may seem to be free services, but in reality they are typically financed by selling advertising. Some also make money by selling information about your online activities and interests to advertisers.Search EnginesThe newest wave of search engines, including Microsoft Bing and Google Squared, not only search for content but also make choices among content to deliver more targeted results. Such search engines allow you, for example, to ask for a list of female tennis stars from 1900, on and they then assemble a table of them for you. Table B shows some common search tools with their URLs and an indication of whether they offer the ability to catalog pages in directories.Search ToolURLTypeAskengineBingengineDogpileengineGoogleengine/directoryMSNengine/directoryYahoo!engine/directoryHow Search Engines WorkSo how do search engines work? You can search for information by going to the search engine’s website and typing your search text, which is comprised of one or more keywords or keyword phrases. For example, to find information about the international space station, you could type space station in the search engine’s search text box and press the Enter key. You can narrow your search by specifying that you want to view links to certain types of results such as images, maps, or videos. You can get more targeted search results by honing your searching technique. Effective searching is a skill that you gain through practice. For example, typing space station in a search engine’s web page could easily return more than eighty million results. If what you really need is the cost to build the station, consider a more targeted keyword phrase like “space station cost.” Search engines provide advanced search options, which you can use to include or exclude certain results. For example, you can exclude pages with certain domain suffixes (such as .com and .net) to limit your search results to educational and government sites. Table C offers some ways you can narrow your search by entering your keywords in various ways.ItemWhat It DoesExampleQuotes (“”)Instruction to use exact word or words in the exact order given“Pearl Harbor”Minus symbol (-)Excludes words preceded by the minus symbol from the searchjaguar –carWildcard (*)Treat the asterisk as a placeholder for any possible word*bird for bluebird, redbird, etc.OrAllow either one word or the otherEconomy 2010 or Economy 2011Metasearch EnginesA metasearch engine, such as , searches keywords across several websites at the same time. For example, imagine you need to fly from Atlanta to Seattle. Instead of checking available flights on three different airline websites, you can use a metasearch engine to check all of the airline sites at once. ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download