HTML, CSS, JavaScript, Indexes and Page Rank
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Transcript HTML, CSS, JavaScript, Indexes and Page Rank
Lesson Objectives
Aims
You should know about:
1.3.4 – Web Technologies
(a)HTML, CSS and Java Script
(b)Search Engine Indexing
(c)Page Rank Algorithm
(d)Server and Client side processing
Indexing
• Search engines collect information about webpages using
automated bots (programs) called web spiders.
• These bots scour the internet, following links and recording
keywords and the addresses where the keywords are found.
• This information is then transmitted back to the search engine
provider, for example Google or Yahoo.
• The information sent back is then ordered and stored according
to an index by keywords, for example
• When users are using search engines they are not searching the
WWW, they’re simply searching the search engine’s index of the
web. This approach means that results can be returned very
quickly.
Page Rank
The PageRank algorithm is Google’s way of ensuring that it returns the
best possible webpages in response to users’ searches.
It was named after its inventor, Larry Page. The PageRank algorithm works
by counting the number of links to a page from other websites. This gives
Google a rough estimate of how important a website is; more important
websites are returned higher up the search results. The information about
webpages (like the number of links) is gathered by an automated web
spider called Googlebot.
The algorithm represents all the webpages as vertices on a directed
graph data structure and the hyperlinks between pages are stored as
edges within the same structure. Vertices are assigned a numerical value
representing their importance (based on the number of links to them).
PageRank is no longer the only algorithm used by Google but it was the
first and is still the best known.
Task
• Find out:
– How Google started and what their big
idea was
– Why Google was different to other search
engines of the time
– What the PageRank algorithm actually is
and what it’s weaknesses are
HTML
• Spec says you need to know:
<HTML>
<HEAD>
<TITLE>
<BODY>
<H1><H2><H3>
<IMG>
<A>
<DIV>
<FORM>
<INPUT>
<P>
<LI>
<OL>
<UL>
<SCRIPT>
HTML
• You already know HTML from GCSE and
if you don’t, its really easy.
• But you will get nowhere if you don’t
learn through practise.
• So you’re going to make a simple
website.
Task
• Make a site which has:
– At least 3 pages
– Images, titles, and hyperlinks (anchor points, internal and
external)
– At least one bullet point list (see how to make numbered lists
too)
– A table of information
– A form which collects information about visitors (using a
range of controls)
– An email link, which automatically sets the subject line
– You are NOT allowed to use ANY kind of visual editor, all
code to be done in Notepad ++
Stuck? Google tutorials! The web is full of them. You may want
to start at W3CSchools.
CSS
• Extend your site to use CSS
– Give each main element a style
– Specify how the table should look
– Change the following at least once:
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Background-color
Border-color
Border-style
Border-width
Font-family
Font-size
Height
Width
– Apply your CSS to each page in the site using the
appropriate tag
Java Script
• You will not be expected to write javascript in
your exam, however you are:
“…expected to be able to write and follow…”
the code.
• How much you need to know is limited.
• Again, practise is the only way, your task is to
work through:
• http://www.w3schools.com/Js/
Review/Success Criteria