Finish HTML Spreadsheets CS 110 Fall 2005
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Finish HTML Spreadsheets CS 110 Fall 2005 Homework 1 Grades Index1.html – 50 points Index2.html – 50 points Myexperiment.html – 5 points Homework 1 Grades Lose 10 points • Webpage fails to include Name and biographical paragraph • HTML not used properly (ex: no using the <HTML>, <head>, and <body> tags) • Not submitted through toolkit Homework 1 Grading 50 points • Page not visible from the web Minimizing Work Digital information poses unique challenges • Effortless to create (sometimes) • Effortless to copy (always) • Effortless to reuse (?) What makes reuse difficult? Finishing HTML Examples of Reuse Web page reuse • What’s easy? • What’s hard? Reuse: What can we do? Make it easy to change things you anticipate • Absolute vs. local filename references • Keep images in special directory • Tables CSS: Cascading Style Sheets Update the “look” of a web page without changing the “content” • Why should form and function be implicitly connected? Tutorial at: http://www.w3schools.com/css/css_intro.asp My Example at: http://www.people.virginia.edu/dcb8j/index21.html CSS Example All paragraphs <p> use italic font All tables <table> should be in red All web pages on your site should switch from Times font to Lucida font The Style Hierarchy Browser default External style sheet Internal style sheet • inside <head> tag Inline style • inside HTML element Details A web page needs two pages now HTML file • References a CSS file in the <head> CSS file • Associates HTML tags with formatting details Example http://www.w3schools.com/css/show it.asp?filename=ex1 http://www.w3schools.com/css/show it.asp?filename=ex2 Computers in our Lives 1983 Time’s “Person” of the Year Where were we headed? Time (January 2, 1983) This most visible aspect of the computer revolution, the video game, is its least significant. But even if the buzz and clang of the arcades is largely a teen-age fad, doomed to go the way of Rubik's Cube and the Hula Hoop, it is nonetheless a remarkable phenomenon. About 20 corporations are selling some 250 different game cassettes for roughly $2 billion this year. According to some estimates, more than half of all the personal computers bought for home use are devoted mainly to games. Otto Friedrich. Reported by Michael Mortiz/San Francisco, J. Madeleine Nash/Chicago and Peter Stoler/New York Time (January 2, 1983) Apart from games, the two things that the computer does best have wide implications but are quite basic. One is simply computation, manipulating thousands of numbers per second. The other is the ability to store, sort through and rapidly retrieve immense amounts of information. More than half of all employed Americans now earn their living not by producing things but as "knowledge workers," exchanging various kinds of information, and the personal computer stands ready to change how all of them do their jobs. Otto Friedrich. Reported by Michael Mortiz/San Francisco, J. Madeleine Nash/Chicago and Peter Stoler/New York Time (January 2, 1983) Frank Herringer, a group vice president of Transamerica Corp., installed an Apple in his suburban home in Lafayette, Calif., and spent a weekend analyzing various proposals for Transamerica's $300 million takeover of the New York insurance brokerage firm of Fred S. James Co. Inc. "It allowed me to get a good feel for the critical numbers," says Herringer. "I could work through alternative options, and there were no leaks." Otto Friedrich. Reported by Michael Mortiz/San Francisco, J. Madeleine Nash/Chicago and Peter Stoler/New York Spreadsheets Give people new ways to “tinker” with problems and their data Motivate the mass production of personal computers (IBM didn’t enter until after the success of spreadsheets on early Apples) Spreadsheet History 1961 – Technical paper 1970 – US Patent 1979 – VisiCalc • When the professor found an error, he had to tediously erase and rewrite a number of sequential entries in the table… Spreadsheet History 1970, early software patent • Patent rejected as “a mathematical invention” • “something does not cease to become patentable merely because the point of novelty is in an algorithm” (wikipedia.com) Wayback History The printing press • 1071 (in China) • 1234 (movable type in Korea) • 1450 (widespread use by Gutenburg) Wayback History 100 years for the “invention” of page numbers, tables of contents, indices Why? • Few books, few scholars • Many books, many readers What? • Metaphorical “science” of images gives way to scientific method of words/numbers Spreadsheets Before mass production • Few scholars, few computers • Accounting software was customized and not reusable After spreadsheets • Standardized representation • New ways of thinking Data to Knowledge 123421.08234, 120934.09034, 4509.34249, 29094.0923, 23.03, 0.09934, 98340.0934, 130938.909, 23409.09345, 3459.945, 345.0, 450, 787405.05, 8984.94, 2808909.0, 45899.45450945, 894534.345, 45782, 434972.45092, 40827, 2, 2895.902902, 2330.000, 2945.898 Organization Knowledge What’s dependent on what? What are multiple “samples” of same data? What’s a sensible way to store? Spreadsheet Organization Each column stores a type of data • Age, number of friends, address Each row stores multiple types of data that are related by something • Sampled at same time • Attributes of one object Why not swap rows/columns? Planning Upfront Errors with organization are costly • (Columns) Address lumped in one cell Separate by zip code? Separate by street? • (Rows) Data recorded annually How to compare January performance across years? Revealing the Power Standardized organization permits quick mathematical relationships • Compute average sales for all Januaries in the ’90s • Computer average sales for 2003 • How many students scored above 90? • Excluding the failing grades, what is the standard deviation Enough Rope to Hang Yourself Many spreadsheet values are computed from other values • How? Is it clear if there is an error? Moving data around in spreadsheets can disrupt naming convention used to compute values • How? Is it clear if there is an error? Topics File extension (xls) Toolbars Basic and complex equations Deleting and adding cells Copying cell contents Copying equations (absolute and relative) Format cells Cell borders Graphs
