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LIS650 lecture 3 Minor CSS, Krug on web site design Thomas Krichel 2005-02-18.

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Presentation on theme: "LIS650 lecture 3 Minor CSS, Krug on web site design Thomas Krichel 2005-02-18."— Presentation transcript:

1 LIS650 lecture 3 Minor CSS, Krug on web site design Thomas Krichel

2 today advanced CSS –crafty selectors –select properties Information Architecture

3 ORing selectors When we write elementary several selectors separated by commas, we refer to all of them Example h1,.heading {text-align: center} will center all and all elements that are that are in the heading class.

4 fun with selectors * selects any element. E selects any element called E E F selects any F element that is in the contents of an E element, as a child, grand-child etc E > F selects any F tag that is a child of an E element. This is more restrictive than the previous selector. E:first-child selects E when E is the first child of its enclosing element E:link selects an E element if it is in the contents of an element

5 more selectors E:visited selects element E if E if it is in the contents of a link and the link has been visited. E:active, E:hover, E:focus selects element E during certain user actions with the mouse. E:lang(c) selects element E if it is in the human language c E + F selects any F element immediately preceded by a sibling element E.

6 more selectors E[a] selects any E element with an attribute "a", whatever the value E[a="v"] select any E element whose "a" attribute value is exactly equal to "v". E[a~="v"] selects any element E whose "a" attribute value is a list of space-separated values, one of which is exactly equal to "v". Useful for classes, because you can put an element into several classes, separated by blanks.

7 more selectors E[lang|="en"] selects any E element whose "lang" attribute has a hyphen-separated list of values beginning (from the left) with "en". This would select all en languages, be they en-us or en-gb E:first-letter selects the first letter in the content of element E E:first-word selects the first word in the contents of element E

8 convenient shorthand We have already seen some. E.m is a convenient shorthand for E[class~="m"] E#myid is a convenient shorthand for E[id="myid"].m is a convenient shorthand for *.m

9 E:before and E:after E:before or E:after can be used to add contents before or after a element E. We will deal come to these when we discuss generated contents properties. This will be coming up after the examples for selectors that we will discuss now.

10 examples h1, h2, h3 { font-family: sans-serif } h1 { color: red } em { color: red } h1 em { color: blue } div p *[href] body > p { line-height: 1.3 } div ol > li p h1 + p {text-indent: 0}

11 more example h1 + h2 {margin-top: -5mm} h1.opener + h2 {margin-top: -5mm} h1[title] {color: blue} span[class="example"] {color: blue } span[hello="Cleveland"][id="Columbus"] { color: blue} a[rel~="copyright"] {color: red} a[href=""] {background-color: grey} *[lang=fr] {display: none}

12 more examples *[lang|="en"] {color : red }.dialog.romeo {voice-family: "Lawrence Olivier", charles, male} a:link {color: red} /* unvisited links */ a:visited {color: blue} /* visited links */ a:hover {color: yellow} /* user hovers */ a:active {color: lime} /* active links */ a.external:visited {color: blue}

13 more examples html:lang(fr) { quotes: '« ' ' »' } html:lang(de) { quotes: '' '} *:lang(fr) > q { quotes: '« ' ' »' } *:lang(de) > q { quotes: '' '} (quotation style depending on the surrounding language, not the language of the quote!)

14 more examples a[rel~="copyright"] a[href=""] div > p:first-child a:focus:hover p > * > p div[class~="ny"][id="albany"]

15 example: drop caps with uppercase CSS p { font-size: 12pt; line-height: 12pt } p:first-letter { font-size: 200%; font-style: italic; font- weight: bold; float: left } span { text-transform: uppercase } HTML The first few words of an article in The Economist.

16 generated contents properties generated contents is, for example, the bullet appearing in front of a list item. {content:} can be used with the :before and :after selectors.The content can be –a text string –a url(URL) where the contents is to be found –a attr(att) where att is the name of the attribute, the content of which is being inserted Example p.note:before {content: "note"} will insert the string "note" before any paragraph in the class 'note'.

17 generated contents properties II Here are some counter properties –{counter-reset: counter} resets a counter counter –{counter-increment: counter} increments a counter –{counter(counter)} uses the counter Example h1:before {counter-increment: chapter_counter; counter-reset: section_counter; content: "Chapter " counter(chapter_counter) ":"} and then we can use h2 for the sections, of course! browser support uncertain!

18 user interface properties I There is a {cursor:} property to change the shape of the cursor. It takes the following values –auto-- crosshair-- default –pointer (something suggesting a link) –e-resize –ne-resize –nw-resize –n-resize –se-resize –sw-resize, --s-resize –w-resiz (Indicate that some edge is to be moved) –text (usually as an I) --wait (watch or hourglass) –help (question mark or balloon) –url (with a uri to svg file, that has the graphic to show) use these to totally confuse your users

19 paged media support I CSS has the concept of a page box in which paged output should be placed rule can be used to specify the size of the {size: 8.5in 11in} Valid values are one or two lengths and they words portrait and landscape. The latter will depend on the default print sheet size, country- specific.

20 paged media support II You can add {margin: }, {margin-top: }, {margin- left: }, and {margin-right: } properties. They will add to the margins that the printer will set by default. The default printer margins are beyond your control. You can add a {marks: crop} property to add crop marks You can add a {mark: cross} property to create registration marks.

21 paged media support III You can use three pseudoclasses to specify special cases –:first for the first page –:left for any left page –:right for any right page Example :first {margin-top: 3in}

22 named pages You can give a page rule an optional name. rotated { size: landscape} Then you can use this with the page property to specify specific ways to print things. Example table {page: rotated} will print the table on a landscape sheet. This comes in handy for bulky tables.

23 actual page breaking Pages will break if –the current page box flows over or if –a new page format is being used with a {page: } property You can take some control with the {page-break- before: } and {page-break-after: } properties. They take the values –auto– always – avoid– left– right The latter two make sure that the element is on a left or right page. Sometimes this will require two page breaks.

24 more examples I have made a stolen and simplified example available for three column layout, with flexible middle column, css_layout/triple_column.html Unfortunately, this example relies a lot on dimensions that are fixed in pixels.

25 Web site design This is supposed to be a big topic in the LIS community. There are a lot of articles about using individual web sites, but there is little scientific material out there related to actual design. But it really comes down to common sense. There is no absolute right/wrong.

26 Learn from some experts –Experts discussed here Krug –not technical Nielsen –has tons of technical advice –weak on overall site design Morville and Rosenfeld –site architecture focus, but mainly common-sensical blah blah –Much of their advice discusses active web sites, not passive ones as the ones that we will build here.

27 Krug's book Short Deals mainly with the issue of how to build commercial web sites. Here user confusion is the cause of lost money. He mainly deals with sites that have –extensive scale –searching and browsing –user interaction Our sites for this course do not have these features.

28 Krug's advice Krug's rule #1: Dont make me think. –a site should be obvious –if it can not be obvious, it must be self-explanatory Things that make think –non-standard terms jobs employment opportunities job-o-rama –links and buttons that are not obvious to find

29 search example Contrast – – for search. Note, however, that search forms are not part of this course.

30 How people use the web Received wisdom would suggest –people read the page –then make the best decision. That is wrong. Instead, people –scan pages –look for something that seems vaguely related to the current aim –click on it if clickable User satisfice (term by Herbert Simon, a cross between satisfying and sufficing)

31 why do they do that? Why do users satisfice? –Users are in a hurry. –The penalty for a wrong guess is low. –Weighing option does not seem much help. –Guessing is more fun. Users don't figure out how things work. They muddle through –It does not matter how things work –When they have found something that is useful to them, users stick with it.

32 Krug's advice Create clear visual hierarchy. –the more important something is, the more prominent it should be –things that relate logically should relate visually –things that are part of something else should be nested visually within it. Use conventions –they have proven useful –users have seen them before Break pages into separate parts Make obvious what is clickable Reduce visual noise.

33 Krug's advice Krug's second law: it does not matter how many times I have to click as long as each click is a mindless, unambiguous choice. Krug's third law: Get rid of half the words on each page, and then get rid of half of what is left. –no happy talk –no instructions

34 Building navigation For commercial web sites, people are usually trying to find something. It is more difficult than in a shop –no sense of scale –no sense of direction –no sense of location Navigation can –give users something to hold on to –tell users what is here –explain users how to use the site –give confidence in the site builder

35 Navigation elements Site ID Sections of items utilities –link to home page –link to search page –separate instructions sheet Current location needs to be highlighted.

36 ways to do navigation Breadcrumbs like "store > fruit & veg > tomato" Tabs, like the ones seen in –Krug's favorite. A table on the left or right hand side that stays the same –will do just fine for us Pull-down menus Rollovers

37 navigational elements on the page All pages except should have navigation except perhaps –home page –search page –instructions pages Page names are also important –every page needs one –in the frame of contents that is unique to the page –the name needs to be prominent –the name needs to match what users click to get there.

38 Home page design For large site, it is a mission impossible But above all it has to convey the big picture –tagline clear and informative just long enough differentiating clear benefit showing lively, personable and sometimes clever –welcome blurb –but no mission statement

39 bad home pages put a banner add even though they don't need it let deals drive the home page promote everything are greedy for user data

40 That's about all from Krug, folks The rest of the book is about how to do usability testing. But there is a second edition out there, on which I will work for the next course.

41 W3C tips on anchors When calling the user to action, use brief but meaningful link text that: –provides some information when read out of context –explains what the link offers –doesn't talk about mechanics –is not a verb phrase

42 W3C tips on anchors Bad: To download W3C's editor/browser Amaya, click here. Bad: To download Amaya, go to the Amaya Website and get the necessary software. Good: Get Amaya! Bad: Tell me more about Amaya Good: Tell me more about Amaya

43 W3C tips for headings Use for your top heading. If it is too big a font in the most common browsers, you can scale it down. But then you have a scale down other headers correspondingly.

44 W3C tips for alt= If the image is simply decorated text, put the text in the alt attribute If the image is used to create bullets in a list, a horizontal line, or other similar decoration, it is fine to have an empty alt=, but it is better to use things like list-style-image in CSS If the image presents a lot of important information, try to summarize it in a short line for the alt attribute and add a longdesc= link to a more detailed

45 accessibility There are two versions of the Web Contents Accessibility Guideline (WCAG) published by the W3C. Version 1 had 14 guidelines and each guideline has 1 or more checkpoints. It is stable. Version 2 is being developed right now supposed to be –easier to understand –easier to implement –easier to test It still looks rather rough!

46 WGAG principles 4 principles –Content must be perceivable –Interface elements in the content must be operable. –Content and controls must be understandable –Content must be robust enough to work with current and future Web technologies 3 implementation docs –1 for HTML –1 for CSS –1 that is technology independent

47 WCGA HTML tasks Set a DTD using the DTD declaration Set a Use the to give a document's author, e.g. This page was written by Karl Marx If you have a glossary, have it ed to with the rel=glossary in the.

48 WCAG Do not use redirects that are timed, only immediate redirects. (redirects are covered later) Do not refresh page by themselves. Reveal the structure of the site through the element. Use to to give the structure of the document. Don't use them for visual effects. Use to give the language for the document

49 WCAG Note changes of language with the lang= attribute. e.g. voiture will avoid it being pronounced as "voter" by an English reading software. Use and rather than and. Use with the title= to explain an abbreviation eg LIU. Same with for accronyms.

50 WCAG Use and for quotes, but don't use for formatting. Avoid. In nested lists, use compound counters. In tables, use the headers= and scope= attributes to explain the structure of your table. Avoid using tables for layout. If you must do it, only use, and elements and border= cellspacing= and cellpadding= attributes.

51 WCAG Provide useful link text. If you have an image and text for your link, combine them in the same. You can use the accesskey= attribute with to give users a key that is used to access a link. Hide the navigation links for challenged media. Use alt="" for purely decorative images. Avoid ASCII art. Use emoticons judiciously. Do not embed text in images.

52 WCAG Do not use background images. Whenever possible use markup and text, rather than images, to convey information. (there are other guidelines but they talk about things that we did not cover here, such as frames, forms, scripting.)

53 Please shutdown the computers when you are done. Thank you for your attention!

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