What is HTML? HTML Tags. HTML Element Syntax. HTML Attributes. <tagname>content</tagname> DR.SHA/WEB TECHNOLOGY/2013/2014

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1 1 What is HTML? HTML is a language for describing web pages. HTML stands for Hyper Text Markup Language HTML is a markup language A markup language is a set of markup tags The tags describe document content HTML documents contain HTML tags and plain text HTML documents are also called web pages 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 <tagname>content</tagname> 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 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"

2 2 HTML Headings Headings are defined with the <h1> to <h6> tags. <h1> defines the most important heading. <h6> defines the least important heading. <h1>this is a heading</h1> <h2>this is a heading</h2> <h3>this is a heading</h3> HTML Lines The <hr> tag creates a horizontal line in an HTML page. The hr element can be used to separate content: <p>this is a paragraph.</p> <hr> <p>this is a paragraph.</p> <hr> <p>this is a paragraph.</p> HTML Paragraphs Paragraphs are defined with the <p> tag. <p>this is a paragraph</p> <p>this is another paragraph</p> HTML Line Breaks Use the <br> tag if you want a line break (a new line) without starting a new paragraph: <p>this is<br>a para<br>graph with line breaks</p>

3 3 HTML Formatting Tags HTML uses tags like <b> and <i> for formatting output, like bold or italic text. HTML Comment Tags Comments the HTML source by using the following syntax:  HTML Hyperlinks (Links) The HTML <a> tag defines a hyperlink. A hyperlink (or link) is a word, group of words, or image that you can click on to jump to another document. When we move the cursor over a link in a Web page, the arrow will turn into a little hand. The most important attribute of the <a> element is the href attribute, which indicates the link's destination. HTML Link Syntax The HTML code for a link is simple. It looks like this: <a href="url">link text</a> The href attribute specifies the destination of a link. <a href=" W3Schools</a>

4 4 HTML Images - The <img> Tag and the Src Attribute In HTML, images are defined with the <img> tag. The <img> tag is empty, which means that it contains attributes only, and has no closing tag. To display an image on a page, you need to use the src attribute. Src stands for "source". The value of the src attribute is the URL of the image you want to display. Syntax for defining an image: <img src="url" alt="some_text"> The URL points to the location where the image is stored. An image named "boat.gif", located in the "images" directory on " has the URL: HTML Tables Tables are defined with the <table> tag. A table is divided into rows with the <tr> tag. (tr stands for table row) A row is divided into data cells with the <td> tag. (td stands for table data) A row can also be divided into headings with the <th> tag. (th stands for table heading) The <td> elements are the data containers in the table. The <td> elements can contain all sorts of HTML elements like text, images, lists, other tables, etc. The width of a table can be defined using CSS. <table style="width:300px"> <tr> <td>jill</td> <td>smith</td> <td>50</td> </tr> <tr> <td>eve</td> <td>jackson</td>

5 5 <td>94</td> </tr> </table> HTML Unordered Lists An unordered list starts with the <ul> tag. Each list item starts with the <li> tag. The list items are marked with bullets (typically small black circles). <ul> <li>coffee</li> <li>milk</li> </ul> How the HTML code above looks in a browser: Coffee Milk HTML Ordered Lists An ordered list starts with the <ol> tag. Each list item starts with the <li> tag. The list items are marked with numbers. <ol> <li>coffee</li> <li>milk</li> </ol> How the HTML code above looks in a browser: 1. Coffee 2. Milk HTML Description Lists A description list is a list of terms/names, with a description of each term/name. The <dl> tag defines a description list.

6 6 The <dl> tag is used in conjunction with <dt> (defines terms/names) and <dd> (describes each term/name): <dl> <dt>coffee</dt> <dd>- black hot drink</dd> <dt>milk</dt> <dd>- white cold drink</dd> </dl> Cascading Style Sheets (CSS) What is CSS? CSS stands for Cascading Style Sheets Styles define how to display HTML elements External Style Sheets can save a lot of work External Style Sheets are stored in CSS files CSS Syntax A CSS rule has two main parts: a selector, and one or more declarations: The selector is normally the HTML element we want to style. Each declaration consists of a property and a value. The property is the style attribute we want to change. Each property has a value. Three Ways to Insert CSS There are three ways of inserting a style sheet:

7 7 External style sheet Internal style sheet Inline style External Style Sheet An external style sheet is ideal when the style is applied to many pages. With an external style sheet, we can change the look of an entire Web site by changing one file. Each page must link to the style sheet using the <link> tag. The <link> tag goes inside the head section: <head> <link rel="stylesheet" type="text/css" href="mystyle.css"> </head> An external style sheet can be written in any text editor. The file should not contain any html tags. Style sheet should be saved with a.css extension. An example of a style sheet file is shown below: hr {color:sienna;} p {margin-left:20px;} body {background-image:url("images/background.gif");} Internal Style Sheet An internal style sheet should be used when a single document has a unique style. We define internal styles in the head section of an HTML page, by using the <style> tag, like this: <head> <style> hr {color:sienna;} p {margin-left:20px;} body {background-image:url("images/background.gif");} </style> </head> Inline Styles An inline style loses many of the advantages of style sheets by mixing content with presentation. Use this method sparingly! To use inline styles you use the style attribute in the relevant tag. The style attribute can contain any CSS property. The example shows how to change the color and the left margin of a paragraph: <p style="color:sienna;margin-left:20px;">this is a paragraph.</p>

8 8 Background Color The background-color property specifies the background color of an element. The background color of a page is defined in the body selector: body {background-color:#b0c4de;} With CSS, a color is most often specified by: a HEX value - like "#ff0000" an RGB value - like "rgb(255,0,0)" a color name - like "red" In the example below, the h1, p, and div elements have different background colors: h1 {background-color:#6495ed;} p {background-color:#e0ffff;} div {background-color:#b0c4de;} Background Image The background-image property specifies an image to use as the background of an element. By default, the image is repeated so it covers the entire element. The background image for a page can be set like this: body {background-image:url("paper.gif");} Text Color The color property is used to set the color of the text. With CSS, a color is most often specified by: a HEX value - like "#ff0000" an RGB value - like "rgb(255,0,0)" a color name - like "red"

9 9 body {color:blue;} h1 {color:#00ff00;} h2 {color:rgb(255,0,0);} Text Alignment The text-align property is used to set the horizontal alignment of a text. Text can be centered, or aligned to the left or right, or justified. When text-align is set to "justify", each line is stretched so that every line has equal width, and the left and right margins are straight. h1 {text-align:center;} p.date {text-align:right;} p.main {text-align:justify;} Text Indentation The text-indent property is used to specify the indentation of the first line of a text. p {text-indent:50px;} Font Family The font family of a text is set with the font-family property. The font-family property should hold several font names as a "fallback" system. If the browser does not support the first font, it tries the next font. Note: If the name of a font family is more than one word, it must be in quotation marks, like: "Times New Roman". More than one font family is specified in a comma-separated list: p{font-family:"times New Roman", Times, serif;} Font Style The font-style property is mostly used to specify italic text.

10 10 This property has three values: normal - The text is shown normally italic - The text is shown in italics oblique - The text is "leaning" (oblique is very similar to italic, but less supported) p.normal {font-style:normal;} p.italic {font-style:italic;} p.oblique {font-style:oblique;} Font Size The font-size property sets the size of the text. Always use the proper HTML tags, like <h1> - <h6> for headings and <p> for paragraphs. The font-size value can be an absolute, or relative size. Absolute size: Sets the text to a specified size Does not allow a user to change the text size in all browsers (bad for accessibility reasons) Absolute size is useful when the physical size of the output is known Relative size: Sets the size relative to surrounding elements Allows a user to change the text size in browsers Set Font Size with Pixels Setting the text size with pixels gives you full control over the text size: h1 {font-size:40px;} h2 {font-size:30px;} p {font-size:14px;} Styling Links Links can be styled with any CSS property (e.g. color, font-family, background, etc.). In addition, links can be styled differently depending on what state they are in. The four links states are:

11 11 a:link - a normal, unvisited link a:visited - a link the user has visited a:hover - a link when the user mouse over it a:active - a link the moment it is clicked a:link {color:#ff0000;} /* unvisited link */ a:visited {color:#00ff00;} /* visited link */ a:hover {color:#ff00ff;} /* mouse over link */ a:active {color:#0000ff;} /* selected link */ Background Color The background-color property specifies the background color for links: a:link {background-color:#b2ff99;} a:visited {background-color:#ffff85;} a:hover {background-color:#ff704d;} a:active {background-color:#ff704d;} List In HTML, there are two types of lists: unordered lists - the list items are marked with bullets ordered lists - the list items are marked with numbers or letters With CSS, lists can be styled further, and images can be used as the list item marker. Different List Item Markers The type of list item marker is specified with the list-style-type property: ul.a {list-style-type: circle;} ul.b {list-style-type: square;} ol.c {list-style-type: upper-roman;} ol.d {list-style-type: lower-alpha;} An Image as the List Item Marker To specify an image as the list item marker, use the list-style-image property:

12 12 ul { list-style-image: url('sqpurple.gif'); } JavaScript JavaScript is a Scripting Language JavaScript is the scripting language of the Web. A scripting language is a lightweight programming language. JavaScript is programming code that can be inserted into HTML pages. JavaScript code can be executed by all modern web browsers. JavaScript How To JavaScripts in HTML must be inserted between <script> and </script> tags. JavaScripts can be put in the <body> and in the <head> section of an HTML page. The <script> Tag To insert a JavaScript into an HTML page, use the <script> tag. The <script> and </script> tells where the JavaScript starts and ends. The lines between the <script> and </script> contain the JavaScript: <!DOCTYPE html> <html> <body>.. <script>

13 13 document.write("<h1>this is a heading</h1>"); document.write("<p>this is a paragraph</p>"); </script>.. </body> </html> JavaScript Functions and Events The JavaScript statements, in the example above, are executed while the page loads. More often, we want to execute code when an event occurs, like when the user clicks a button. If we put JavaScript code inside a function, we can call that function when an event occurs. You will learn much more about JavaScript functions and events in later chapters. A JavaScript Function in <head> <!DOCTYPE html> <html> <head> <script> function myfunction() { document.getelementbyid("demo").innerhtml="my First JavaScript Function"; } </script> </head> <body> <h1>my Web Page</h1> <p id="demo">a Paragraph</p> <button type="button" onclick="myfunction()">try it</button> </body> </html> A JavaScript Function in <body>

14 14 <!DOCTYPE html> <html> <body> <h1>my Web Page</h1> <p id="demo">a Paragraph</p> <button type="button" onclick="myfunction()">try it</button> <script> function myfunction() { document.getelementbyid("demo").innerhtml="my First JavaScript Function"; } </script> </body> </html> External JavaScripts Scripts can also be placed in external files. External files often contain code to be used by several different web pages. External JavaScript files have the file extension.js. To use an external script, point to the.js file in the "src" attribute of the <script> tag: <!DOCTYPE html> <html> <body> <script src="myscript.js"></script> </body> </html> Writing to The Document Output <!DOCTYPE html> <html> <body>

15 15 <h1>my First Web Page</h1> <script> document.write("<p>my First JavaScript</p>"); </script> </body> </html> <!DOCTYPE html> <html> <body> <h1>my First Web Page</h1> <p>my First Paragraph.</p> <button onclick="myfunction()">try it</button> <script> function myfunction() { document.write("oops! The document disappeared!"); } </script> </body> </html> JavaScript Statements JavaScript statements are "commands" to the browser. The purpose of the statements is to tell the browser what to do. This JavaScript statement tells the browser to write "Hello Dolly" inside an HTML element with id="demo": document.getelementbyid("demo").innerhtml="hello Dolly"; JavaScript Comments Comments will not be executed by JavaScript. Comments can be added to explain the JavaScript, or to make the code more readable.

16 16 Single line comments start with //. // Write to a heading: document.getelementbyid("myh1").innerhtml="welcome to my Homepage"; JavaScript Multi-Line Comments Multi line comments start with /* and end with */. /* The code below will write to a heading and to a paragraph, and will represent the start of my homepage: */ document.getelementbyid("myh1").innerhtml="welcome to my Homepage"; document.getelementbyid("myp").innerhtml="this is my first paragraph.";