CISC 103 WEB DEVELOPMENT BASICS WEB SITE HTTPS

CISC 103 WEB DEVELOPMENT BASICS: • WEB SITE: • HTTPS: //WWW. EECIS. UDEL. EDU/~YARRINGT/103 • ALL ASSIGNMENTS AND INFORMATION IS POSTED ON WEB SITE • ALL ASSIGNMENTS MUST BE SUBMITTED VIA SAKAI • EMAIL: YARRINGT@UDEL. EDU • ALL LABS ARE DUE THURSDAY AT MIDNIGHT • ALL HOMEWORKS ARE DUE SUNDAY AT MIDNIGHT • UNLESS OTHERWISE NOTED • INSTALL NOTEPAD++ OR TEXT WRANGLER ON YOUR COMPUTER

INTRO TO THE INTERNET • INTERNET: • A NETWORK OF NETWORK • THE INTERNET CONSISTS OF THOUSANDS OF SMALLER NETWORKS • THEY MAY BE EDUCATIONAL, COMMERCIAL, NONPROFIT, MILITARY ORGANIZATIONS, ETC. 2 -2

BRIEF HISTORY • INTERNET HISTORY • • • BEGAN WITH 1969’S ARPANET FOR US DEPT. OF DEFENSE 62 COMPUTERS IN 1974 500 COMPUTERS IN 1983 28, 000 COMPUTERS IN 1987 EARLY 1990 S, MULTIMEDIA (WWW) BECAME AVAILABLE ON INTERNET 2 -3

HOW DOES THE INTERNET WORK? • PROTOCOLS • SET OF RULES • INTERNET USES TCP/IP • RULES USED FOR ALL INTERNET TRANSACTIONS • BASE PROTOCOL ON WHICH ALL OTHER PROTOCOLS ARE BUILT 2 -4

HOW DOES THE INTERNET WORK? • TCP • DEALS WITH TRANSFER OF DATA • HOW IT IS BROKEN UP AND REASSEMBLED TO BE SENT ACROSS THE INTERNET • PACKETS • FIXED-LENGTH BLOCKS OF DATA • FILES ARE BROKEN UP INTO PACKETS • NOT ALL PACKETS FROM THE SAME FILE FOLLOW THE SAME PATH • DATA IS REASSEMBLED AT THE OTHER END • IP ADDRESSES • INTERNET PROTOCOL ADDRESS – A UNIQUE ADDRESS THAT IDENTIFIES EVERY COMPUTER AND DEVICE CONNECTED TO THE INTERNET 2 -5

KEY INTERNET MODEL: • CLIENT/SERVER MODEL • BUILT ON TOP OF TCP/IP • CLIENT: A COMPUTER REQUESTING DATA OR SERVICES • SERVER: A HOST COMPUTER, A CENTRAL COMPUTER SUPPLYING DATA OR SERVICES REQUESTED OF IT • SERVICES CAN BE REQUESTED OVER THE INTERNET • E. G. , CHECK YOUR BANK ACCOUNT • GETTING EMAIL • DOWNLOADING WEB PAGE • OFTEN MULTIPLE CLIENTS SHARE THE SERVICES OF ONE SERVER 2 -6

WWW • THE WORLD WIDE WEB: • USES CLIENT-SERVER MODEL • CLIENT : YOUR BROWSER • BROWSER REQUESTS WEB PAGE FROM WEB SERVER, • WHEN IT GETS THE WEB PAGE, IT DISPLAYS THE WEB PAGE • SERVER: A COMPUTER OR SET OF COMPUTERS (ELSEWHERE) THAT GIVES WEB PAGES TO CLIENTS. • CLIENT (BROWSER) REQUESTS WEB PAGES, IMAGES, SOUNDS, MOVIES, ETC FROM SERVER. • IF SERVER CAN LOCATE IT, IT SENDS IT BACK TO BROWSER • IF IT CAN’T LOCATE IT, IT SENDS BACK AN ERROR 2 -7

WWW • BROWSERS DO TWO KEY THINGS: • LOCATE WEB SITES VIA UNIQUE ADDRESSES (URL) • READ WEB PAGES AND DISPLAY THEM (DISPLAYS HTML CODE, CSS, JAVASCRIPT, ETC. ) 2 -8

WWW: URL • A WEBSITE’S UNIQUE ADDRESS • IT CONSISTS OF • • THE WEB COMMUNICATION PROTOCOL, HTTP THE DOMAIN NAME OF THE WEB SERVER THE DIRECTORY OR FOLDER ON THAT SERVER THE FILE WITHIN THE DIRECTORY, INCLUDING OPTIONAL EXTENSION HTTP: //WWW. UDEL. EDU/FALL 13/WEBFILE. HTML protocol domain name directory file name. extension 2 -9

CLIENTS, SERVERS AND THE WEB • HTTP: • THE INTERNET PROTOCOL USED TO ACCESS THE WORLD WIDE WEB • RULES THAT GOVERN COMMUNICATION BETWEEN A WEB CLIENT AND A WEB SERVER • STANDS FOR HYPERTEXT TRANSFER PROTOCOL • HTTPS • THE SECURE VERSION OF HTTP

THE WEB • HTML • THE LANGUAGE USED IN WRITING AND PUBLISHING WEB PAGES • THE SET OF TAGS USED FORMATTING AND LINKING TO OTHER DOCUMENTS ON THE WEB • NOT A PROGRAMMING LANGUAGE (BUT IT CAN CONTAIN PROGRAMMING CODE) • HYPERTEXT LINKS CONNECT ONE WEB DOCUMENT TO ANOTHER 2 -11

OTHER TERMS • CSS – • CASCADING STYLE SHEETS • USED FOR STYLING WEB PAGE • HTML IS FORMATTING • CSS IS USED FOR STYLING • JAVASCRIPT • CLIENT-SIDE SCRIPTING LANGUAGE • NOT STAND-ALONE, BUT AN ADD-ON TO HTML • MOST POPULAR SCRIPTING LANGUAGE