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DOM, Multimedia and Widgets

DOM, Multimedia and Widgets. 20 February 2014. Trees and DOM. Trees. Navigating a Tree. NodeA.firstChild  = NodeA1 NodeA.lastChild  = NodeA3 NodeA1.parentNode  = NodeA NodeA1.nextSibling = NodeA2 NodeA3.prevSibling = NodeA2 NodeA.lastChild.firstChild  = NodeA3a. Relating To HTML.

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DOM, Multimedia and Widgets

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  1. DOM, Multimedia and Widgets 20February 2014

  2. Trees and DOM

  3. Trees

  4. Navigating a Tree • NodeA.firstChild = NodeA1 • NodeA.lastChild = NodeA3 • NodeA1.parentNode = NodeA • NodeA1.nextSibling = NodeA2 • NodeA3.prevSibling = NodeA2 • NodeA.lastChild.firstChild = NodeA3a

  5. Relating To HTML • Look at Inspect Element Root = HTML Children and siblings • Structure is called the DOM Document Object Model • CSS will allow us to format selectively based on the tree

  6. CSS Selectors • context tag { • Applies to any tag inside context • Space is a descendant selector • context > tag { • Applies to any tag directly inside context • > is a child selector • Context + tag { • Applies only to a tag that DIRECTLY follows a context • + is an adjacent sibling selector

  7. Fun Additions to Websites

  8. Sound Options • You can add it to the page – not recommended • Widgets (coming next) • Natively in HTML5 <audio controls> <source src="h.wav" type="audio/wav"> </audio> Warning: may not work until uploaded

  9. Videos • Options • Widgets (coming next) • Iframes (Youtube) • Natively in HTML5 <video controls> <source src="m.mp4" type="video/mp4" /> </video> Warning: may not work until uploaded

  10. Other Documents • Object <object data="cauliflower.pdf"></object> • pdf: can open in a browser, but not part of your website

  11. JavaScript and Widgets

  12. Review: Viewing a Web Page SERVER web page repository WEB PAGE instructions stores information and instructions BROWSER retrieves web page and follows instructions 2 1 3 Server Client Web Server Pages Browser

  13. Dynamic Web Pages • Two places you can change • Browser: JavaScript • Server: php • General rule: • do it in the browser if you can • Why? • Distribute the work • Consider the difference in the time function… 2 1 3 Server Client Web Server Pages Browser

  14. What is JavaScript? • Functions • simple programming tool • dynamic text • react to events • read and write HTML elements • w3schools

  15. HTML Content CSS Presentation JavaScript Behavior Three Legged Stool

  16. Widgets • A chunk of code that you can embed in an existing environment • Differences • Resides: desktop or web • Embedding: any page or application or limited • Runs: your machine or server

  17. Widget Websites • Lots of sites • See resources • Or just Google • Let’s add some to a web page • Adding • Formatting: • Enclose in div • position and format • Warning: make sure that your browser isn’t blocking them

  18. Problems with Widgets • They have divs in them that you can’t see • Implicaton: if you format all divs, it applies to the ones in the widget • Solution: name all divs with class or use section or main, header, … • They may use & or blank in URLs • Implication: won’t validate • Solution: replace all &s with &amp; and all blanks with %20 • They may be old • Don’t use if too many obsolete tags

  19. Steps for adding a widget • Assure that you have no unnamed divs • Layout your page with a placeholder div that is the size of the widget that you are going to add • Add the widget inside the div • Assure that it looks the way that you want • Format the embedded code without any changes • Replace all inline formatting with classes and css • Assure that it still looks right • Eliminate any unneeded tags or css entries • Assure that it still looks right • Replace all & and blanks as needed • Validate

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