Computer Sciences Department

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3 Hyper Text Markup Language (HTML) and Extensible Hyper Text Markup Language (XHTML) You have to Study from the textbook and 3

4 HTML Introduction With HTML you can create your own Web site. What is HTML? HTML is a language for describing web pages. HTML stands for Hyper Text Markup Language HTML is not a programming language, it is a markup language A markup language is a set of markup tags The purpose of the tags are to describe page content 4

5 Example of html file <!DOCTYPE html> <html>.. <body> </body> <h1>my First Heading</h1> <p>my first paragraph.</p> </html> 5

6 HTML Tags HTML markup tags are usually called HTML tags HTML tags are keywords (tag names) surrounded by angle brackets like <html> HTML tags normally come in pairs like <b> and </b> The first tag in a pair is the start tag, the second tag is the end tag The end tag is written like the start tag, with a forward slash before the tag name Start and end tags are also called opening tags and closing tags HTML tags are not case sensitive: <P> means the same as <p>. Many web sites use uppercase HTML tags. 6

7 HTML Elements "HTML tags" and "HTML elements" are often used to describe the same thing. HTML elements are written with a start tag, with an end tag, with the content in between. The HTML element is everything from the start tag to the end tag: HTML container element: Start tag: <p> Content: This is a paragraph. End tag: </p> 7

8 Nested HTML Elements (This example contains 4 HTML elements) <!DOCTYPE html> <html> <body> </html> </body> <h1>my First Heading</h1> <p>my first paragraph.</p> 8

9 HTML Element Syntax An HTML element starts with a start tag / opening tag An HTML element ends with an end tag / closing tag The element content is everything between the start and the end tag Some HTML elements have empty content Empty elements are closed in the start tag Most HTML elements can have attributes 9

10 Empty HTML Elements HTML elements with no content are called empty elements. <br> is an empty element without a closing tag (the <br> tag defines a line break). Tip: In XHTML, all elements must be closed. Adding a slash inside the start tag, like <br />, is the proper way of closing empty elements in XHTML (and XML). 10

11 HTML Documents = Web Pages HTML documents describe web pages HTML documents contain HTML tags and plain text HTML documents are also called web pages 11

12 Web Browsers The purpose of a web browser (Chrome, Internet Explorer, Firefox) is to read HTML documents and display them as web pages. The browser does not display the HTML tags, but uses the tags to interpret the content of the page. 12

13 HTML Page Structure a visualization of an HTML page structure 13

14 HTML Headings HTML headings are defined with the <h1> to <h6> tags. 14

15 HTML Paragraphs HTML paragraphs are defined with the <p> tag. 15

16 HTML Links A hyperlink is an element, a text, or an image that you can click on, and jump to another document. HTML links are defined with the <a> tag. 16

17 HTML Images HTML images are defined with the <img> tag. The alt attribute specifies an alternate text for the image, if it cannot be displayed. The alt attribute is required. A web page will not validate correctly without it width and height attributes: the values are specified in pixels (with or without px after the value): 17

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19 HTML Attributes HTML elements can have attributes Attributes provide additional information about an element. Attributes are always specified in the start tag Attributes come in name/value pairs like: name="value" 19

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21 Always Quote Attribute Values Attribute values should always be enclosed in quotes. Double style quotes are the most common, but single style quotes are also allowed. Tip: In some rare situations, when the attribute value itself contains quotes, it is necessary to use single quotes: name='john "ShotGun" Nelson Newer versions of (X)HTML will demand lowercase attributes. 21

22 HTML / XHTML Standard Event Attributes Standard Event Attributes: HTML 4 added the ability to let events trigger actions in a browser, like starting a JavaScript when a user clicks on an element. Next is the standard event attributes that can be inserted into HTML / XHTML elements to define event actions. (some) 22

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25 HTML Comments 25

26 HTML Color Names RGB 140 Color Names are Supported by All Browsers 140 color names are defined in the HTML5 and CSS3 color specifications. 17 colors are from the HTML specification, 123 colors are from the CSS specification. The following table lists them all, along with their hexadecimal values Tip: The 17 colors from the HTML specification are: aqua, black, blue, fuchsia, gray, green, lime, maroon, navy, olive, orange, purple, red, silver, teal, white, and yellow 26

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HTML Classes Classing HTML elements, makes it possible to define CSS styles for classes of elements. http://www.w3schools.

30 HTML Classes Classing HTML elements, makes it possible to define CSS styles for classes of elements. Equal styles for equal classes, or different styles for different classes 30

31 HTML Character Sets To display an HTML page correctly, the browser must know what character-set to use. The character-set for the early world wide web was ASCII. ASCII supports the numbers from 0-9, the uppercase and lowercase English alphabet, and some special characters. Since many countries use characters which are not a part of ASCII, the default character-set for modern browsers is ISO If a web page uses a different character-set than ISO , it should be specified in the <meta> tag. 31

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33 HTML Symbol Entities This entity reference includes mathematical symbols, Greek characters, various arrows, technical symbols and shapes. Note: Entity names are case sensitive. 33

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36 Button The <button> tag defines a clickable button. Inside a <button> element you can put content, like text or images. This is the difference between this element and buttons created with the < input> element 36

37 Table and caption Definition and Usage The <caption> tag defines a table caption. The <caption> tag must be inserted immediately after the <table> tag. You can specify only one caption per table. Tip: By default, the table caption will be center-aligned above a table. However, the CSS properties "text-align" and "caption-side" can be used to align and place the caption. 37

38 Table The <td> tag defines a standard cell in an HTML table. An HTML table has two kinds of cells: Header cells - contains header information (created with the <th> element) Standard cells - contains data (created with the <td> element) The text in <th> elements are bold and centered by default. The text in <td> elements are regular and left-aligned by default 38

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40 Complex HTML table A more complex HTML table may also include <caption>, <col>, <colgroup>, <thead>, <tfoot>, and <tbody> elements. 40

41 Table and caption 41

42 Different Styles for Different Tables ryhtml_table_id1 42

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44 XHTML Introduction XHTML stands for EXtensible HyperText Markup Language XHTML is almost identical to HTML 4.01 XHTML is a stricter and cleaner version of HTML XHTML is HTML defined as an XML application 44

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46 An XHTML DTD describes the allowed syntax and grammar of XHTML markup. XHTML/XML namespaces are used for providing uniquely named elements and attributes used in an XHTML/XML document. 46

47 The Most Important Differences from HTML DOCUMENT STRUCTURE XHTML DOCTYPE is mandatory The XML namespace attribute in <html> is mandatory <html>, <head>, <title>, and <body> is mandatory ELEMENT SYNTAX XHTML elements must be properly nested XHTML elements must always be closed XHTML elements must be in lowercase XHTML documents must have one root element ATTRIBUTE SYNTAX XHTML attribute names must be in lower case XHTML attribute values must be quoted XHTML attribute minimization is forbidden 47

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51 XHTML - Attributes XHTML attributes are HTML attributes written as XML XHTML Attributes - Syntax Rules Attribute names must be in lower case Attribute values must be quoted Attribute minimization is forbidden 51

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54 HTML 4.01 / XHTML 1.0 Tag Reference 54

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Web Development. Owen Sacco. ICS2205/ICS2230 Web Intelligence

Web Development. Owen Sacco. ICS2205/ICS2230 Web Intelligence Web Development Owen Sacco ICS2205/ICS2230 Web Intelligence Introduction Client-Side scripting involves using programming technologies to build web pages and applications that are run on the client (i.e.