The WWW
Source: CSTA model Curriculum 2009
Source: CSTA model Curriculum 2009
The web was invented by Tim Berners-Lee in 1990 and 1991. The World Wide Web has three major components. The user runs a web browser, which formats and displays web pages. Web servers store collections of web pages (called web sites) and data. Users and web servers are connected by the Internet, which passes data between them.
A user’s browser connects to a web server and requests a web page, which is transmitted back to the user’s computer over the Internet.
Web pages have links to other web pages; following these links is the primary technique for traversing the web. Web pages are identified with URLs (Uniform Resource Locaters). A URL consists of a scheme (e.g. http://), a host (e.g. www.google.com), a port (e.g. 80) which is usually omitted, and a path or other page identifying information (e.g. /newuser/login.html).
Search engines are a central part of the web. They consist of “inverted lists,” or indices, which associate words with the URLs of web pages on which those words appear. These lists are created and updated by computer programs called “spiders” which read web pages and update the lists.
The World Wide Web gives every person with a computer connected to the Internet easy access to a vast amount of information and resources. However we should know how to of use the web in a safe manner:
1. Whenever a file is downloaded from a web site to your own computer, there is a possibility that that file contains a virus. Files from well-known companies are generally (but not always) safe, and files from file sharing sites are often infected.
2. We should be careful with giving personal information (such as name, age, address, parent’s credit card number) on a web page
A popular use of the Internet is to send email (electronic mail). An email address consists of a user name (1 to 64 characters long), the @ symbol, and a domain name, such as example.com.
Three guidelines for responsible use of email:
1.Do not forward email if you dont know the its real content.
2. Do not respond to email from anyone you don’t know;
3.Never write anything in an email that you would not want your parents and teachers to read.
A user’s browser connects to a web server and requests a web page, which is transmitted back to the user’s computer over the Internet.
Web pages have links to other web pages; following these links is the primary technique for traversing the web. Web pages are identified with URLs (Uniform Resource Locaters). A URL consists of a scheme (e.g. http://), a host (e.g. www.google.com), a port (e.g. 80) which is usually omitted, and a path or other page identifying information (e.g. /newuser/login.html).
Search engines are a central part of the web. They consist of “inverted lists,” or indices, which associate words with the URLs of web pages on which those words appear. These lists are created and updated by computer programs called “spiders” which read web pages and update the lists.
The World Wide Web gives every person with a computer connected to the Internet easy access to a vast amount of information and resources. However we should know how to of use the web in a safe manner:
1. Whenever a file is downloaded from a web site to your own computer, there is a possibility that that file contains a virus. Files from well-known companies are generally (but not always) safe, and files from file sharing sites are often infected.
2. We should be careful with giving personal information (such as name, age, address, parent’s credit card number) on a web page
A popular use of the Internet is to send email (electronic mail). An email address consists of a user name (1 to 64 characters long), the @ symbol, and a domain name, such as example.com.
Three guidelines for responsible use of email:
1.Do not forward email if you dont know the its real content.
2. Do not respond to email from anyone you don’t know;
3.Never write anything in an email that you would not want your parents and teachers to read.
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