Lesson Objectives Aims You should know about: 1.3.4 – Web Technologies HTML, CSS and Java Script Search Engine Indexing Page Rank Algorithm 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: 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
“…expected to be able to write and follow…” the code. 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