A-level Computing/AQA/Computer Components, The Stored Program Concept and the Internet/Webpage Design/Web page construction

HTML & style sheets Web pages are now an essential part of how many people live their lives and perform their jobs. More and more computer functions are now moving to web based applications and it is important that you are familiar with this technology. Structure of a Web Page You might have made some web sites at secondary school using WYSIWYG editors such as Front Page and Dreamweaver. For the A-Level Computing course we are going to take a look at the code that these editors produce, and how to structure webpages with code. Open this wikibook page in any browser and click CTRL+U in Firefox / Chrome or View -> Page Source in Internet Explorer, you should have the webpage code in front of you. HTML Hypertext Markup Language, the language used for building web pages All web pages have the following basic structure: HTML - specifies that this is a web page Head - contains the title of the page with code and css includes Body - displays the main page content Which can be represented in HTML code using the following Tags: <html> <head> <title>...</title> </head> <body>...</body> </html> Tags Web pages are built out of tags. These tags define what is on the page and how it should be structured. There are two types of tags that you can use, and all tags should be written in lower case. <h1>A Book About Computing</h1> <hr /> On line one you can see the first type, it has an opening tag <h1> something in the middle "A book About Computing" and a closing tag</h1>. This tells us that everything between these tags should be treated as a level one heading (h1). On line two you can see the second type of tag, there is no closing tag, the tag is entirely self contained. The <hr /> stands for a horizontal rule, a line across the page. Search Engine Optimisation Some tags are supposed to be used in certain locations on a webpage and have special functions that may not result in any change to the content or layout of that page. There are special tags reserved to help a webpage get found and ranked by search engines. These tags live in the <head>...</head> section of a webpage. Come to my site first - this places a title on the top of the browser (NOT the top of a web page) - so that search engines can better categorise web pages, they know what the site is about - you used to be able to add keywords to tell search engines what a site was about. This was open to abuse as web site designers just chucked in all the words they could think of and this method isn't used much any more, however, you still need to know it. Example: Drawing a website Draw a web-browser display for the following: <html> <head> <title>Kempoogle</title> <meta name="Description" content="The best site in the world"> </head> <body>hello world!</body> </html> Kempoogle hello world!  Notice that the <title>Kempoogle</title> appears as the title of the browser window, but the <meta name="Description" content="The best site in the world"> is not visible to the user. It is merely there to help web search engines categorise the page. Exercise: Web Site Basics What are the top most level tags on a website: and Write the code to create a webpage that has the banner title of "Moogle - shopping site" and has a meta description of "The best site in the world": <html> <head> <title>Moogle - shopping site</title> <meta name="Description" content="The best site in the world"> </head> <body>...</body> </html> How might you use the <head> section of a web page to increase the page's ranking in search engines? Adjust the <meta name=Description ...> and <meta name=Keywords ...> tags 6 Extension: Teach Yourself HTML The web is full of free resources to skill yourself up and there is nothing to stop you becoming a top notch web designer. The questions here are suitable to get you through this course with some added elements. If you want to get really good at the vaste array of web technologies out there you should be looking to teach yourself. A great place to get started is the w3schools website where you can take courses in: HTML Javascript, the programming language behind interactive websites If you want to learn about the code that builds dynamic webpages, including Facebook, check out: PHP Block-level tags Block tags allow you to give a tag attributes such as padding and margin. This allows you to insert tags into various parts of a page and rely on the other elements there to move to make space for it without worrying about overlap. The tags you need to know are: <h#></h#> - headings <hr /> - horizontal rules <p></p> - paragraphs <br /> - make a new line, <ol></ol> - ordered lists <ul></ul> - unordered lists <li></li> - list items <div></div> - div Horizontal Rule <hr /> - puts a horizontal line across the page where ever you are, useful for breaking up pages <html> <head> <title>Examples of horizontal rule</title> </head> <body> Normal Text <hr /> Normal Text <hr /> Normal Text </body> </html> Examples of horizontal rule Normal Text Normal Text Normal Text Headings <h#></h#> - heading tags make any text between the tags a heading, the higher the number (h#) the less significant the heading <html> <head> <title>Examples of headings</title> </head> <body> <h1>Heading 1</h1> <h2>Heading 2</h2> <h3>Heading 3</h3> Normal Text </body> </html> The code above produces the following: Examples of headings Heading 1 Heading 2 Heading 3 Normal Text For all following examples the html, body and head tags have been left out. This doesn't mean they don't exist and if you code it you must include them. Exercise: Headings Draw out what the following codes would produce: <h1>Years</h1> <h2>Year 12</h2><hr /> <h2>Year 13</h2> <h1>Staff</h1> -- Years Year 12 Year 13 Staff <h1>Introduction</h1> <h2>My Life</h2> <h2>My Cats</h2> <h2>My Dogs</h2> <h3>Barry</h3> <h3>Aubrey</h3> <h3>Rex</h3> <h1>Theories</h1> <h1>Conclusions</h1> -- Introduction My Life My Cats My Dogs Barry Aubrey Rex Theories Conclusions Write the code to produce the following headings: -- Output Devices Monitors Speakers <h1>Output Devices</h1> <h2>Monitors</h2> <h2>Speakers</h2> -- Team Goalies Defenders Midfield Strikers Rooney Socrates Stadia Old Trafford <h1>Team</h1> <h2>Goalies</h2> <h2>Defenders</h2> <h2>Midfield</h2> <h2>Strikers</h2> <h3>Rooney</h3> <h3>Socrates</h3> <h1>Stadia</h1> <h2>Old Trafford</h2> Lists There are 2 types of list that you need to know, ordered lists (<ol></ol>) and unordered lists (<ul></ul>). Each has individual list items (<li></li>) that hold all the data. Unordered Lists <ul></ul> give you a list made up of bullet points <ul> <li>apples</li> <li>oranges</li> <li>pears</li> </ul> the code above would give you: Examples of unordered list apples oranges pears <ol> <li>apples</li> <li>oranges</li> <li>pears</li> </ol> the code above would give you: Examples of ordered list apples oranges pears As you can see above the individual list items are contained within the <li></li> brackets. Exercise: HTML Lists Write HTML to create the following lists: Geoffrey Bungle Zippy George <ul> <li>Geoffrey</li> <li>Bungle</li> <li>Zippy</li> <li>George</li> </ul> Wittgenstein Augustine Heidegger Marcel <ol> <li>Wittgenstein</li> <li>Augustine</li> <li>Heidegger</li> <li>Marcel</li> </ol> What would the following code output: <ul> <li>Kierkegaard</li> <li>Jaspers</li> <li>Frankl</li> <li>Rand</li> </ul> Kierkegaard Jaspers Frankl Rand What is wrong with the following code to print an ordered list: <ul> <li>Kierkegaard<li> <li>Jaspers</li> <li>Frankl</ul> <li>Rand</li> </ul> the following code is corrected with comments <ol> <!--this needs to be <ol> as it is an ordered list--> <li>Kierkegaard</li> <!--this needs a closing /--> <li>Jaspers</li> <li>Frankl</li> <!--this had the incorrect closing tag--> <li>Rand</li> </ol> <!--this needs to be </ol> as it is an ordered list--> Breaking pages up A Div element is used to divide a web page into sections <div></div> - this takes up space on a page and the page will appear larger the more of them you place in. A Paragraph <p></p>, allows you to structure your text like you would if you were writing an essay. A Break <br />, creates a new line. Inline tags These don't take up any physical space on the page (they don't cause a new line) and can overlap each other. They are: <span></span> - break the page into sections but don't create new lines, <strong></strong> - make text bold, <em></em> - make text itallic, <a></a> - create a link or an anchor, <a href="http://www.google.com"> link </a> produces the following:link <img /> - add an image <img src="http://en.wikipedia.org/wiki/File:Google 2011 logo.png" /> produces the following: 200px Let's take a look at a quick example: Example: HTML worked example <h2>Ditty</h2> I tell you naught for your comfort, <br /> Yea, naught for your desire,<br /> Save that the sky grows <strong>darker</strong> yet <br /> And the sea rises <strong>higher</strong> <hr /> - G.K.Chesterton, <em>The Ballad of the White Horse</em>(1911) The output of the above is as follows: DittyI tell you naught for your comfort, Yea, naught for your desire, Save that the sky grows darker yet And the sea rises higher</p> - G.K.Chesterton, The Ballad of the White Horse (1911) As you can see the layout of the HTML code doesn't always reflect how it will look on screen, remember even if your code looks like it has line breaks, if you don't use block-level tags such as <br /> or a <p> you won't get any breaks. Now it's time to test your knowledge: Exercise: Inline Tags Write the code to produce the following output: Hello how are you? <em>Hello</em> <strong>how</strong> are <strong><em>you</em></strong>? :I'm finethank you <strong>I'm</strong> <em>fine</em><br /> thank you :This is a link to the bbc website. This is a <a href="http://www.bbc.co.uk">link</a> to the <em>bbc website</em>. The Quick Brown Fox Jumped over the Lazy Dog <p>The <strong>Quick Brown Fox</strong></p> <p>Jumped over the <em>Lazy Dog</em></p> Bold Link to google Itallic {apologies for the trick question!} <ul> <li><em>Bold</em></li> <li><strong>Link to google</strong></li> <li><a href="http://www.google.com">Itallic</a></li> </ul> Write the code to create the following page linking an image called cat.jpg Cat picture This is a picture of a cat: 200px <html> <head> <title>Cat picture</title> </head> <body> This is a picture of a <em>cat</em>:<br/> <img src="cat.jpg"/> </body> </html> Write the code to create the following page linking an image called dog.jpg to the page http://college.ac.uk Dog picture This picture of a dog links to my college's website: 200px <html> <head> <title>Dog picture</title> </head> <body> This picture of a <strong>dog</strong> links to my college's website:<br/> <a href="http://college.ac.uk"><img src="dog.jpg"></a> </body> </html> What does the following code produce: The invention<br /> of <strong>weights</strong> and <strong>measures</strong><br /> Makes robbery easier<br /><hr /> <em>- Chuang Tzu</em> Quoted from: Merton, Thomas. (1969). The Way of Chuang Tzu. New York: New Directions. The invention of weights and measures Makes robbery easier - Chuang Tzu <p><em>Modern art has taken the wrong turn in abandoning the search for the <br /><strong>meaning of existence</strong></em> <br /> in</p><p>order to affirm the value of the <strong>individual</strong> for his own sake</p><p><em>- Andrei Tarkovsky</em></p> Quoted from: Tarkovsky, Andrei (1989). Sculpting in Time. University of Texas Press note that the line breaks at the end of each line of code has no effect, we only place line breaks with <br /> and <p> Modern art has taken the wrong turn in abandoning the search for the meaning of existence in order to affirm the value of the individual for his own sake - Andrei Tarkovsky Write the full html page code for the following webpage: Car heaven Car heaven Welcome to the car site Cars Vans Bikes This week 30% discount <html> <head> <title>Car heaven</title> </head> <body> <h1>Car heaven</h1> <p>Welcome to <em>the</em> car site</p> <ul> <li>Cars</li> <li>Vans</li> <li>Bikes</li> </ul> <p>This week <strong>30%</strong> discount</p> </body> </html> Write the full html page code for the following webpage, where the image address is: contempt.jpg with alt text of contempt and the web address is: http://bbc.co.uk Education Contempt without a gentle contempt for education, no gentleman's education is complete 200px Learn more Click here to learn more <html> <head> <title>Education</title> </head> <body> <h1>Contempt</h1> <p>without a gentle <strong>contempt</strong> for education,<br /> no gentleman's education is complete</p> <img src="contempt.jpg" alt="contempt"> <h2>Learn More</h2> <p>Click <a href="http://bbc.co.uk">here</a> to go to learn more</p> </body> </html> Comments Sometimes you want to write something in the HTML code of a webpage to help you understand the code better. This is called a comment and is an ubiquitous feature in any computing language. Comments don't perform any computing function and don't display on a finished Web page, they are merely there for the web designer to use so that they can understand the page better. For HTML we use the following tags: <html> <head> <title>Love</title> </head> <body> <h1>What Love is</h1> "Love means to love that which is unlovable; or it is no virtue at all." <!--Quote from G. K. Chesterton (1874-1936)--> </body> </html> In the example above, the line starting with the <!−− and ending in −−> is a comment. A comment block start with <! and ends with > and you can have as many comments as you like between those tags, as long as they start and end with −−. Everything in between these comment tags will not be displayed on the screen, producing this: Love What Love is "Love means to love that which is unlovable; or it is no virtue at all." Exercise: Comments For the following code sketch what it outputs: <html> <head> <title>Friendship</title> </head> <body> <h1>Hello</h1> <p>Can I be your friend?</p> <ol> <li>Yes</li> <li>No</li> <!--<li>Maybe</li>--> </ol> <!--What a horrible question.--> </body> </html> Friendship Hello Can I be your friend? Yes No 6 Extension: HTML 5 thumb|center|100px What we have been learning so far are the very basics of web design. If you like what you've been doing you better check out HTML5. HTML5 is starting to make websites fully interactive with the ability to quickly embed videos and interact with web pages. Over the next few years you'll increasingly see applications moving over to this new technology, so get with the program and start learning at w3schools.