AIM Class3

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Class Goals

1. Introduce the concept of standardization and validating documents
2. Introduce web accessiblity
3. Reinforce previously learned (DID) image formats and compression

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Compliance and Verification of Documents

Review

1. Who creates the standards?

2. Are the standards mandatory for browser developers and for those who post content online?

Compliant XHTML/CSS

1. What do you need in order to make a document "verifiable"?

2. How can you "verify" a document?

Web Accessibility

1. What is web accessibility?

2. Why is web accessibility important?

3. How can you make a site more accessible?

Images on the Web and Compression Schemes

Formats

Main image formats for web publishing at this time: jpg, gif, png, svg (however the most accessible to older browsers are jpg and gif).

JPG

When to use: an image that has a lot of detail (like a photograph).

Algorithm used: JPG

Pros and Cons:

1. Lossy
2. Works well with detailed images

GIF

When to use: an image that has broad areas of color, an animated image, or an image with transparency (when using png is not desirable)

Algorithm used: LZW

Pros and Cons:

1. Limited to 256 colors
2. Compression works well with broad areas of color, but not with details
3. Patent
4. Animation (flip-book type animation, as a layered stack)

PNG

When to use: When target audience browser support is known, or when transparency is needed

Algorithm used: PNG

Pros and Cons:

1. Lossless
2. Limited support in older browsers
3. Potentially larger file size
4. Transparency

SVG

SVG

Copyright

Fair Use, Copyright Issues, Creative Commons

Wrapping Text

Review: block-level vs. inline elements (how does this affect flow?)

"Clearing" flowing content using the clear attribute with the br element (left, right, all)

Images

Deprecated: Using the align attribute (align="right" means the image goes to the right, the text goes to the left)

CSS

Aligning Text with CSS

Wrapping text around a block-level element (such as an image or div) with CSS

Anchor Tags and Pseudo Classes

Psuedo classes: definition and examples

Links

W3c: http://www.w3.org/

Web Accessibility: http://www.w3.org/WAI/intro/accessibility.php

Overview of Accessibility: http://www.w3.org/WAI/References/QuickTips/Overview.php

Creative Commons: http://creativecommons.org/

Homework

AIM Assignment 3

Reading

ZEN: Chapter 1, pages 34-45; Chapter 4(pages 125-129)

XHTML: Chapter 5, pages 83-98; Chapter 6, 104-115, Chapter 7, pages 117-132