Bridges To Computing

Transcription

1 Bridges To Computing General Information: This document was created for use in the "Bridges to Computing" project of Brooklyn College. You are invited and encouraged to use this presentation to promote computer science education in the U.S. and around the world. For more information about the Bridges Program, please visit our website at: Disclaimers: IMAGES: All images in this presentation were created by our Bridges to Computing staff or were found online through open access media sites and are used under the Creative Commons Attribution-Share Alike 3.0 License. If you believe an image in this presentation is in fact copyrighted material, never intended for creative commons use, please contact us at so that we can remove it from this presentation. LINKS: This document may include links to sites and documents outside of the "Bridges to Computing" domain. The Bridges Program cannot be held responsible for the content of 3 rd party sources and sites.

2 Introduction to Web Programming and Design Lecture 1 Bridges to Computing M. Meyer

3 Topics Markup Languages Definition Motivation Types HTML Overview Rules, validation Examples About semantic markup

4 Question What is a language? Verbal Written Visual Programming Markup Simple Answer: A medium for sharing/exchanging information

5 Markup Languages Markup languages are not the same as programming languages. Programming languages are used to create programs that control the behavior of a machine. C/C++/C#, Java, Processing, Python, JavaScript, PHP, Perl, Markup languages are used for adding information (sometimes called metadata) to text in a way which is distinguishable from that text Latex, SGML, XML, HTML, It is possible to embed programming language statements/commands into a markup language.

6 Editing/Proofreading symbols (a type of markup language)

7 Motivation It is possible to send pictures over the Internet, but pictures are large, fixed and difficult to resize It s very cheap and easy to send plain text over the Internet (ASCII, Unicode). However plain text without formatting is difficult to read Markup languages allow us to add information to text, in a manner that is distinguishable from the text Markup languages can be used to enhance the comprehension/understandability of the text

8 Text vs. Images The letter A. The image Letter A: 1 byte Image A (lettera.gif): 935 bytes

9 Plain Text (difficult to read) Course description: This course will commence with a general introduction to Multi-Media Computing (MMC), and move on to cover a broad range of subjects including: web design, web programming, graphics, animation, simulation, and game design. Discussions will be introductory and emphasis is on the design and creation of a range of artifacts, including: web pages, with HTML and cascading style sheets; interactive, graphical web-based programs; agent-based simulations and simple computer games and narratives. The format consists of alternating lecture/laboratory class sessions, with STRONG emphasis on hands-on learning. Labs and projects are completed in 2- member (optional) groups. (3 credits) Course structure: The following topics will be covered in 4 curricular units: I. Introduction to Web Programming and Web Design Principles of Web Design; HTML; Cascading Style Sheets (CSS) II. Interactive Web Programming and Graphics Processing III. Agents, Simulations and Visualizations NetLogo IV. Game Programming and Narrative Scratch Class sessions will consist of lectures and hands-on labs.

10 Text augmented with presentation markup (easier to understand)

11 Types of Markup Presentational markup: Used by traditional wordprocessing systems, to create a WYSIWYG effect. Examples: add line break, bold face, change font style or color Procedural markup: Provides instructions for programs that are to process the text. Examples: add an image, applet or link to a document Semantic markup: Used to label parts of document and attach additional meaning to those sections. Examples: define the title of a document or declaring that a section of text is an address

12 Markup Languages Key Terminology Tag: A markup construct that begins with < and ends with >. Tags come in three flavors: Start-tags, e.g. <p> End-tags, e.g. </p> Empty-element tags, e.g. <br/> Element: a component that begins with a start-tag and ends with a matching end-tag, or consists only of an emptyelement tag. e.g. <p>hello, world!</p> Attribute: A construct consisting of a name/value pair that exists within a start-tag or empty-element tag. e.g. <img src= button.jpg alt= button />

13 Intro to HTML HTML: Hyper-Text Markup Language HTML is a language web servers can use to communicate with computers via web browsers HTML content is delivered in pages, consisting of plain text interspersed with tags Web pages are stored as files on computers called servers, because they serve (i.e. deliver) the content to the computers that want to look at it Web content pages, documents, are stored in files with names ending in.html or.htm

14 HTML to XHTML to HTML5 XHTML stands for extensible HTML, it s almost identical to HTML 4 XHTML is a stricter and cleaner version of HTML Many pages on the Internet contain bad HTML Browsers are still expected to interpret this bad HTML correctly XHTML is HTML defined as an XML application This allows you to create and define your own tags HTML 5 is the new W3C recommendation (finalized in late 2014). It aims to combine both HTML and XHTML and improve the language with support for the latest multimedia contents.

15 Basic components of a HTML5 document <!DOCTYPE html> <html> <head> <title>simple HTML5 document</title> </head> <body> some contents </body> </html>

16 HTML Pages Can Be Validated You can check your.html documents to see if they are valid by going to the following link: If your html file violates any rules or is missing any required elements, it will generate errors or warnings. HTML5 specific validation can be enabled by More Options

17 Writing HTML Many applications can be used to create HTML documents. No matter what you use, the basic underlying HTML is the same For this class, you will use a text editor to write basic HTML: On a PC, this is Notepad, not WordPad or Word On a Mac, this is TextEdit (in plain text mode, not rtf, and be sure to disable the Smart Quotes feature!) On Linux/Unix, this can be pico or emacs or vi or Text Editor Though, there are many excellent cross-platform text editors available, and many of them are free For this class, you will create a file using a text editor and type content and HTML tags into that file. Follow the lab sheets for detailed instructions In the remainder of these notes, you will find a quick reference to basic HTML tags

18 HTML Tags Reference

19 Page Tags DOCTYPE declaration has to appear at the top! It s an instruction to the web browser about the HTML version All other elements must be between the <html> tags <!DOCTYPE html> <html> <head> <title>page Title (Appears in browser title bar/tab)</title> </head> <body> <h1>an important heading (Appears within the body)</h1> <h2>a slightly less important heading</h2>t here are other sizes, from <h1> (largest) to <h6> (smallest) <p>a simple paragraph</p> </body> <!--Comment goes here --> </html> Note the difference between header, <head>, and heading, <h1>.. <h6>

20 Paragraph Tags Paragraphs: <p>this is the first paragraph.</p> <p>this is the second paragraph.</p> Line breaks: This is the first line.<br /> This is the second line. Division: <div>a specific section of text</div> Inline: <span style= color:red >red text color</span> Note: The div element is very often used with CSS to lay out a web page. Browsers usually place a line break before and after the div element.

21 Character Tags Emphasis: This is <em>interesting</em>! Italics: This is really <i>interesting</i>! Bold: This is <b>boldly interesting</b>! Preformatted Text: <pre> Text in a pre element is displayed in a fixed-width font, and it preserves both spaces and line breaks </pre>

22 Link Tags A link is a tag that directs your browser to another page if the user clicks on the link. The content of the link tag is: 1. The URL where you want the browser to go if the user clicks on the link, and 2. The text that you want the user to see (i.e., the text that the user will click on to activate the link) Examples: This a link to <a href=" This a link to <a href=" target=_blank>google</a> that opens up another window.

23 List Tags Un-ordered list: <ul> <li>the first list item</li> <li>the second list item</li> <li>the third list item</li> </ul> Ordered list: <ol> <li>the first list item</li> <li>the second list item</li> <li>the third list item</li> </ol> Note: You can nest lists!

24 Table Tags Begin a table with <table> End a table with </table> Begin each row with <tr> and end each row with </tr> Begin each column with <td> and end each column with </td> Options (Note: many of these are replaced by CSS in HTML5) borders (e.g. border= 1 ) cellpadding (padding within a cell) cellspacing (spacing between cells) width and height (in pixels) aligning cell content headings Tricks: empty cells (use ) spanning multiple columns (use colspan= 2 ) Coloring cells: <td bgcolor="red">asdf</td>

25 HTML5 Multimedia (w3schools.com) Video Before HTML5, no standard for showing videos on a web page, and plug-ins are used to play them HTML5 introduces the <video> element Example <video width="320" height="240" controls> <source src="movie.mp4" type="video/mp4"> <source src="movie.ogg" type="video/ogg"> Your browser does not support the video tag. </video>

26 Audio HTML5 Multimedia, cont (w3schools.com) HTML5 also introduces the <audio> element Example <audio controls> <source src="horse.ogg" type="audio/ogg"> <source src="horse.mp3" type="audio/mpeg"> Your browser does not support the audio element. </audio>

27 Where to get help HTML Tags: