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CTEC1414 Lecture 19

phones off (please). CTEC1414 Lecture 19. XHTML and CSS Introduction to XHTML and CSS Bharti Patel. Overview. Definition of a webpage Xhtml page structure Elements i d and class attributes Style Sheets Cascading Style Sheets Inline, internal and external style sheets Style rules.

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CTEC1414 Lecture 19

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  1. phones off(please) CTEC1414Lecture 19 XHTML and CSS Introduction to XHTML and CSS Bharti Patel

  2. Overview • Definition of a webpage • Xhtml page structure • Elements • id and class attributes • Style Sheets • Cascading Style Sheets • Inline, internal and external style sheets • Style rules

  3. XML) HyperTextMarkupLanguage What is a Web Page? A web page is a simple text file could be written in Notepad we use JPadPro The text is structured using markup (xhtml) markup simply means adding annotation xhtmlmarkup comprises elements there is a set of elements that we can use The elements represent common features for structure and appearance These include paragraphs, images, headings The page’s appearance is set in a CSS Cascading Style Sheet

  4. What is a Web Page? • Browsers (Internet Explorer, Firefox, Crome) interpret the xhtmlmarkup with the CSS in order to determine how to display the content • The xhtml has a strict syntax / grammar The xhtmlmust be correct The xhtmlcan be validated • CSS has a strict syntax / grammar The CSS must be correct The CSS can be validated

  5. What is a Web Page • Text with coded messages telling a browser what to display. • Text is coded using start and an end tag • The tags and content is called an element • A start tag looks like <h1> • An end tag looks like </h1> • An element looks like <h1> text goes here </h1>

  6. xhtml page structurehtml, head and body elements <?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns = "http://www.w3.org/1999/xhtml" xml:lang ="en"lang = "en"> <head> <title>Title</title> </head> <body> </body> </html> JPadPro creates a web page with this basic structure so you do not need to remember or type it in add your page content with it’s markup here

  7. Basic Structure of a Web Page • an element looks like: • <div>text goes here</div> • the content is between the 2 tags • <div>is a start tag • </div> is an end tag • a tag comprises • a <(less than symbol) • the tag name in lower case • a >(greater than symbol) <?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> "> <htmlxmlns="http://www.w3.org/1999/xhtml"xml:lang="en"lang="en"> <head> <title>Title</title> </head> <body> <div> This is a division element which is usually a large section of your page ..... </div> </body> </html> more page content with it’s markup goes here

  8. Common Elements • divisions / layers • headings • paragraphs • lists • hyperlinks • media - images, videos, sound • tables • forms

  9. Elements • Logical elements • add a logical structure to the text in the page • Physical elements • affect the appearance of the text

  10. Logical Elements include • Headings <h1>text goes here</h1> • Paragraphs <p>this is a paragraph – related text as in English</p> • Divisions <div>This is a div – a chunk of other elements </div> • Spans <span>a small piece of special text</span>

  11. Logical Elements include • Images • Hyperlinks • Tables • Forms • multimedia objects • NOT frames

  12. Physical Elements • Bold • <b></b> • Strong • <strong></strong> • Italic • <i></i> • Headings are also physical – • h1,h2 … h6 changes the size of the text

  13. divs and paragraphs (elements) <div>s are elements for marking up larger chunks (compare with book, chapter) <div>s can contain <p>aragraphs, <h1>eadings and other <div>s <p>aragraphs are elements for marking up a smaller chunk of connected content – as in English. <p>aragraphs can contain <spans>s

  14. h1)eadings and spans (elements) <h1>eadings are for marking up headings at six levels h1 (largest) to h6 (smallest) <span>s are for marking up small chunks of particular significance <h1>eadings and <span>s cannot contain larger chunks - div, paragraphs etc.

  15. id and class (attributes) A page may contain many divs and paragraphs so we use attributes to name these idis an attribute used to uniquelyidentify elements class is an attribute used to identify a group of similar elements

  16. divs and paragraphs (elements)id and class (attributes) <div id="main"> <p class="p1">Anne Other has taught mathematics and computing..... </p> <p class="p2">Since 1975 Anne has.... </p> </div>

  17. Adding XHTML CommentsComments – do not get displayed <!--details correct as of 24-02-12 --> <body> <div id="main"> <p class="p1">Anne Other has taught mathematics and computing..... </p> <p class="p2">Since 1975 Anne has.... </p> </div> </body>

  18. Designing page structure • Single page • Simply use logic to identify the blocks • use id and class as needed • Multiple pages – a web site • Plan shape of each page • give each page an identical structure even if not every page has content in each element • make id and class consistent on all pages

  19. Cascading Style Sheets

  20. Style Sheets Styles are used to define the appearance and layout of the page Appearance = color, font, borders etc Layout = positioning, visual structure Styles are associated with elements Styles are defined in Style Rules Style rules have a format: {property:value}

  21. Cascading Style Seets CSS CSS are file used to contain style rules Cascading because styles cascade down • Browser defaultare browsers style the same? • External CSS (over-ride browserstyles) • Internal CSS (over-ride browserstyles) (over-ride externalCSS styles) • In-line style (over-ride browserstyles) (over-ride externalCSS styles) (over-ride internalCSS styles)

  22. In-line style rules use ONLY for a one-off style change • style element is in the xhtml page original element <h1>one-off heading</h1> styled element <h1 style ="font-family: ‘Comic Sans MS’" > one-off heading style change </h1> The style is linked to ONE element in this case a single <h1> element note 2 sets of quotes single ‘ to contain the font family name double " to contain the attribute value

  23. Stylesheets(internal and external) • Affect groups of elements • When using internal and externalstylesheets we associate an element with a style rule (property:value) • Notation element {property:value}

  24. note the use of the colon to separate property from value Style rules Quotes needed here because of the spaces in the font family name Affecting a single property {property:value} e.g {text-align: right} {letter-spacing: 0.5cm} {font-family: "Comic Sans MS”}

  25. Note the use of the semi-colon to separate each property setting pair Style rule Affecting a multiple properties {property:value;property:value; property:value} e.g {color:red;background-color:white} {font-size: 110%; text-align: right; text-transform: capitalize} Note that when setting the colour of text it is also necessary to set the background colour Note when setting multiple properties this one-per-line layout is easier to read

  26. Styling elements element {property:value} e.g h1 {font-family: "Comic Sans MS"} This will affect ALL <h1>elements element {property:value;property:value} e.g body {color:red; background-color:white} This will affect the whole body of the page the elementwe want to style the style rule for the element

  27. Internal stylesheet • Use when styles apply to one page only <html> <head> <title>this page</title> <style type = "text/css"> h1 {font-family:"Comic Sans MS"} </style> </head> <body> <h1>headings on this page</h1> </body> </html>

  28. External Stylesheet • Use when styles apply to many pages • Define styles in separate css file save as file named: my_styles.css Contents: h1 {font-family:"Comic Sans MS"} • add link in xhtml page to css file • see next slide

  29. External stylesheet – the web page • use when styles apply to many pages <html> <head> <title>this page</title> <linkrel = "stylesheet" type = "text/css“ href = "../css/my_styles.css"/> </head> <body> <h1>heading on all pages look like this</h1> </body> </html>

  30. Why use external stylesheets? • Content is separate from appearance. • One developer does content, one appearance • A stylesheet can affect all pages on a site • The site has a common coherent appearance • A Stylesheet can be validated • In-line styles cannot be validated • Multiple external stylesheets can be used • One for colour, font, text • One for layout – positioning

  31. Why use internal stylesheet and inline styles? • Allows style changes to be made for one page. • An individual developer can customise one page • OR can customise an element, class, id • Can be used to try out styles quickly • test via in-line • copy into an internalstylesheet • transfer to an external stylesheet

  32. Colo(u)r Always set BOTH color – text background-color – background element {color:your-text-color; background-color:your-background-color}

  33. Adding color – names and codes Color names cyan, blue, redetc (limited number) rgbvalues (0-255) or percentages Color codes #rrggbbred green blue h1 {color:cyan; background-color:blue} h1 {color:rgb(0,255,255);background-color:rgb(0%,0%,100%)} h1 {color:#00FFFF; background-color:#0000FF}

  34. Help to choose colors http://www.december.com/html/spec/colorspottable.html http://web.forret.com/tools/color_palette.asp http://ficml.org/jemimap/style/color/wheel.html http://www.w3schools.com/css/css_colors.asp http://www.wellstyled.com/tools/colorscheme2/index-en.html

  35. Changing Fonts • font-family cursive, sans-serif, serif • font-family Arial, “Times New Roman", “Comic Sans MS" • font-size 10pt, 20%, 1.5em, large, smaller • font-style italic, normal • font-weight bold, bolder.. 100,500, normal • font-variant small-caps, normal • font: normal, cursive, small-caps,1.5em Fonts that work in all browsers http://www.ampsoft.net/webdesign-l/WindowsMacFonts.html

  36. Examples /* for all text */ body {color:#FF99CC; background-color:#660099; font-family:"Comic Sans MS"} /* for a class = date */ .date {color:#FFCCFF; background-color:#660099} /* for an id = heading */ #heading {color:#660099; background-color:#CC99FF; font-size:18pt}

  37. Text • text-decoration underline, • text-align left, right, center • text-transform capitalize, lower-case Setting more than one element to the same style Setting h1 and h2 to have the same font h1,h2 {font-family: Arial} Note the comma to separate the 2 elements

  38. Style in named divs • We have used the id attribute to uniquely identify elements • This code sets the colours of the element with id = "main" (a div) • #main{color: red; background-color:white} Note the # symbol references an id

  39. Styles for classes • We have used the class attribute to identify related elements • This code sets the colours of the element with class = "name" (a div) • .name{font-style: italic} Note the . (full stop) symbol references a class

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