Midterm

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Midterm

• October 28

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16 Dithering

• Dithering is using two different colored pixels
  to produce a third color in between.
• It is used when the color needed is not the
  palette
• Or, to reduce the number of colors in the
  palette.
• Or, because the file format does not support
  enough colors

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17Web Crawlers

• Web crawlers start with an initial list of
  pre-determined web pages which they cache, then
  visiting and caching all the pages which are
  linked to that page. This process continues
  recursively.
• Or, Mentioning the 4 policies, and the idea of
  caching and visiting pages
• Or caching pages, and the pages linked to them.

4
Web Crawlers, Common Mistakes

• The idea that web crawlers work when you begin a
  search
• Remember this is too slow
• That web crawlers are the ones searching the
  database for the search engine

5
18 Logical Markup

• It makes it faster to change the appearance of
  web pages because you can change the appearance
  of all of the same element at once.
• Helps search engines to classify your page more
  correctly
• Provides clues about the structure of your
  document to non-traditional browsers
• Visually-impaired
• Text-to speech browsers
• Allows a developer to design an alternate look to
  the site, perhaps for handicapped users

6
Logical Markup Mistakes

• Just saying things like easier to edit
• Separates content from appearance
• Both physical and logical markup do this
• But, if you gave another reason other than easy
  to change the appearance, I accepted this.

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19 Design Principles

• Proximity, Alignment, Contrast, Consistency
  (repetition)
• Had to also provide an example
• If you provided a website instead of an example
  of how it could be used on a website it was
  accepted provided the websites were all different
• Could not put www.cs.sfu.ca down for all 4
  principles
• Alignment isnt just indenting or left-justified
• It is creating a strong visual or horizontal
  virtual line by aligning items of equal importance

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Design Principles, cont.

• Proximity keep related items close, separate
  unrelated items
• Separating unrelated items is not contrast.
• Contrast not just for colors
• If items are different, make them really, really
  different.
• Headings and text should look different
• Text and links
• Consistency not just repeating colors or a
  navigation bar
• Repeating ANY elements from one page to the next
• Colors and navigation bars are examples of
  consistency

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20 10710 to base 3

• Answer 102223
• Those of you who used the division method often
  forgot the 0
• Which is what I did when I used that method
• If you CLEARLY showed your work you received most
  of the credit
• Had to show you understood how the value for the
  individual digits (30, 31, 32 )
• Simple multiplication or math errors lost you 2
  points

10
21 110100112 to Decimal

• Answer 21110
• Almost everyone got this one correct
• Common mistake was to use the values 256, 128,
  64, 32, 16, 8, 4, 2 and forget 1.
• Remember when doing this to go from left to right
  as you write out the numbers
• Left to right will cause problems

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22 Classes and Identifiers Differ

• Classes can be used more than once per page, ids
  can only be used one
• You can create general classes which can be
  applied to many different tags in the same page
• Identifiers can be used as fragments or anchors
  to jump users to parts of a page, classes cannot

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Classes and Identifiers

• If you said that classes were defined with a .
  and identifiers were defined with a this was
  considered trivial and you lost 1 point
• A common mistake was that classes were used
  inline and identifiers were block-level
• Also that classes could be used to make changes
  to the whole page, identifiers just a part of the
  page
• All depends on how its defined.

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23 Generic Class

• Answer
• .bigblue
• color blue (or 00F, or 0000FF)
• font-size 200 (double was not accepted)
• font-family Times (or Times New Roman)

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Generic Class Common Mistakes

• Forgetting to put a at the end of each line
• Using font-color, instead of just color
• Using color blue (like an attribute)
• Using p.bigblue (not generic)
• Can only be applied to paragraphs
• Using divbigblue which is an identifier
• People did pretty good on this one

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24 Table HTML

• lttable border 1gt
• lttrgt
• lttd colspan 2gt applelt/tdgt
• lt/trgt
• lttrgt
• lttd rowspan 2gtpearlt/tdgt
• lttdgtCherrylt/tdgt
• lt/trgt
• lttrgt
• lttdgt Grapefruitlt/tdgtlt/trgt
• lt/tablegt
• each of the lttrgt should be lttr align centergt

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Table Common Mistakes

• Not understanding there were 3 separate rows
• Switching lttdgt with lttrgt
• Using lttdgt and ltthgt with no lttrgt
• Just general confusion about what tags do what
• Many people forgot the rowspan and colspan

17
Table, Cont.

• If you at least had the table correct except for
  the rowspan and colspan of the two tags, you got
  7 points
• Nesting tables was not acceptable. It would not
  look like this
• Did not take off points for not having the border
  attribute
• (I used it so the table lines would appear)
• Did not take off points for not centering the
  text
• Or for trying to center with the wrong tag
• Or for using the wrong attribute
• Or in the wrong place

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Bonus XML

• XML stands for extensible markup language
• It is very similar to HTML
• It is used to markup data, while HTML is used to
  display data
• XML can be transferred easily from one computer
  to another and from one system to another
• Plain text format is readable by humans and
  computers

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25 HTML Mistakes

• There were 15 mistakes in this document
• I will post a version with all of them shown
• You lost points if you pointed out the mistake
  but did not correct it.
• Even though you do not have to use entities to
  display the quote marks, I accepted it
• Showed the potential for needing them and that
  you were thinking

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Midterm Marks

• The average mark is a 62
• This mark is currently a C
• High mark was a 92
• Low was a 0 but partially because a few people
  did not yet take the midterm
• I deliberately want the marks to be low, rather
  than high
• Easier for me to curve up than down
• Better idea of your grade
• The average final mark for this course should be
  between a C/B- average

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Grade Disputes

• If you want to dispute your marks on the midterm
• See me, and only me
• The TAs cannot give you more credit
• If I made a mistake in summing your marks
• See me or the TA
• The TAs can change the marks if it was an error
  in addition on my part
• You must come see me in the next week to dispute
  your marks (before Friday Nov 4)
• You must come see me during office hours or make
  an appointment
• Do NOT show up to class on Friday and try and
  dispute your marks

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Questions?