Web开发基础,赵刚,本课程内容摘要,网站开发基础知识 网站环境构建 管理和配置网站 HTML &CSS JavaScript Asp服务端编程 数据库连结与访问,essential of web development,2,网站开发基础知识,计算机网络基础 网站的含义 网站访问的原理 网页的类型 动态网站技术,essential of web development,3,计算机网络基础,Internet Vs intranet 计算机网络的标准模型 TCP/IP 协议 服务器和客户机 域名 端口,essential of web development,4,Internet VS Intranet,The Internet is a global system of interconnected computer networks that use the standard Internet Protocol Suite (TCP/IP) to serve billions of users worldwide It is a network of networks An intranet is a private computer network that uses Internet Protocol technologies to securely share any part of an organizations information or network operating system within that organization.,essential of web development,5,essential of web development,6,And WWW,WWW（亦作“Web”、“万维网”、“W3”，英文全称为“World Wide Web”） 是一个由许多互相链接的超文本文档组成的系统，通过互联网访问。 万维网联盟（英语：World Wide Web Consortium，简称W3C），又称W3C理事会。1994年10月在麻省理工学院（MIT）计算机科学实验室成立。万维网联盟的创建者是万维网的发明者蒂姆伯纳斯-李。 Whats the difference between the Internet and the World Wide Web (WWW)? WWW = HTML* + HTTP(S) * including CSS, JavaScript, and other browser enabled content WWW 是Internet应用之一,essential of web development,7,Brief History,began as a US Department of Defense network called ARPANET (1960s-70s) initial services: electronic mail, file transfer opened to commercial interests in late 80s WWW created in 1989-91 by Tim Berners-Lee popular web browsers released: Netscape 1994, IE 1995 A opens in 1995; Google January 1996 Chinese First Connection with Internet：Chinese Academics Net, by Computer Applying Technology Institute of Beijing1986， First email, Sep. 14 1987, from CATIB,“Across the Great Wall we can reach every corner in the world” Chinese First Full Internet Connection：NCFC (National Computing and Networking Facility of China) 1994 Baidu1999；Taobao 2003,essential of web development,8,Key aspects of the Internet,Internet is for freedom of information internet Vs. Internet subnetworks can stand on their own computers can dynamically join and leave the network built on open standards; anyone can create a new device lack of centralized control (mostly) everyone can use it with simple, commonly available software,essential of web development,9,Layered architecture,The internet uses a layered hardware/software architecture (OSI model): physical layer: devices such as coaxial cables, fiber-optic lines, modems data link layer: basic hardware protocols (Ethernet, Wi-Fi, DSL, ATM, PPP) network / internet layer: basic software protocol (IP) transport layer: add reliability to network layer (TCP, UDP) application layer: implements specific communication for each kind of program (HTTP, POP3/IMAP, SSH, FTP),essential of web development,10,Internet Protocol (IP),the IP is the underlying system of communication for all data (packets) sent across the internet. each device has a 32-bit IP address as four 8-bit numbers (0-255) find out your internet IP address: find out your local IP address: in a terminal, type: ipconfig (Windows) or ifconfig (Mac/Linux) IP v4 vs. IP v6 (32-b vs. 128-b),essential of web development,11,Transmission Control Protocol (TCP),adds multiple, guaranteed message delivery on top of IP multiplexing: multiple programs using the same IP address port: a number given to each program or service 80: Web browser (443 for secure browsing) 25: email 22: ssh 21: ftp more common ports some programs (QQ, games, streaming media programs) use simpler UDP protocol instead of TCP find out ports used: in a terminal, using netstat (Windows) command using CurrPorts,essential of web development,12,Web servers and browsers,Web server: software that listens for Web page requests part of Windows) C/S Vs B/S model,Web browser: fetches/displays documents from Web servers Microsoft Internet Explorer (IE) Mozilla Firefox Apple Safari Google Chrome Opera,essential of web development,13,Domain Name System (DNS),a set of servers that map written names to IP addresses Example: 219.143.204.38 using Windows command nslookup to find out IP address many systems maintain a local cache called a host file Windows: C:Windowssystem32driversetchosts Mac: /private/etc/hosts Linux: /etc/hosts,essential of web development,14,Uniform Resource Locator (URL),an identifier for the location of a document on a web site a basic URL: http:/www.aw- protocol host path upon entering this URL into the browser, it would: ask the DNS server for the IP address of www.aw- connect to that IP address at port 80 ask the server to GET /info/regesstepp/index.html display the resulting page on the screen,essential of web development,15,More advanced URLs,anchor: jumps to a given section of a web page fetches index.html then jumps down to part of the page labeled downloads port: for web servers on ports other than the default 80 :8080/ query string: a set of parameters passed to a web program parameter q is set to “miserable+failure“ parameter start is set to 10,essentia