Wednesday, February 8, 2017
HTML Basic
HTML Documents
All HTML documents must start with a document type declaration: <!DOCTYPE html>.
The HTML document itself begins with <html> and ends with </html>.
The visible part of the HTML document is between <body> and </body>.
Example:
<!DOCTYPE html>
<html>
<body>
<h1>My First Heading</h1>
<p>My first paragraph.</p>
</body>
</html>
Output:
CSS How To...
When a browser reads a style sheet, it will format the HTML document according to the information in the style sheet.
Three Ways to Insert CSS
- External style sheet
- Internal style sheet
- Inline style
- External Style Sheet
With an external style sheet, you can change the look of an entire website by changing just one file!
Each page must include a reference to the external style sheet file inside the <link> element. The <link> element goes inside the <head> section:
Example:
<!DOCTYPE html>
<html>
<head>
<link rel="stylesheet" type="text/css" href="mystyle.css">
</head>
<body>
<h1>This is a heading</h1>
<p>This is a paragraph.</p>
</body>
</html>
Output:
Thursday, January 26, 2017
CSS Syntax
A CSS rule-set consists of a selector and a declaration block:
CSS selector
The selector points to the HTML element you want to style.
The declaration block contains one or more declarations separated by semicolons.
Each declaration includes a CSS property name and a value, separated by a colon.
A CSS declaration always ends with a semicolon, and declaration blocks are surrounded by curly braces.
In the following example all <p> elements will be center-aligned, with a red text color:
Example:
<!DOCTYPE html>
<html>
<head>
<style>
p {
color: red;
text-align: center;
}
</style>
</head>
<body>
<p>Hello World!</p>
<p>These paragraphs are styled with CSS.</p>
</body>
</html>
Output:
CSS selector
The selector points to the HTML element you want to style.
The declaration block contains one or more declarations separated by semicolons.
Each declaration includes a CSS property name and a value, separated by a colon.
A CSS declaration always ends with a semicolon, and declaration blocks are surrounded by curly braces.
In the following example all <p> elements will be center-aligned, with a red text color:
Example:
<!DOCTYPE html>
<html>
<head>
<style>
p {
color: red;
text-align: center;
}
</style>
</head>
<body>
<p>Hello World!</p>
<p>These paragraphs are styled with CSS.</p>
</body>
</html>
Output:
What is CSS
CSS stands for Cascading Style Sheets
CSS describes how HTML elements are to be displayed on screen, paper, or in other media
CSS saves a lot of work. It can control the layout of multiple web pages all at once
External stylesheets are stored in CSS files
Why Use CSS?
CSS is used to define styles for your web pages, including the design, layout and variations in display for different devices and screen sizes.
CSS Solved a Big Problem
HTML was NEVER intended to contain tags for formatting a web page!
HTML was created to describe the content of a web page, like:
<h1>This is a heading</h1>
<p>This is a paragraph.</p>
When tags like <font>, and color attributes were added to the HTML 3.2 specification, it started a nightmare for web developers. Development of large websites, where fonts and color information were added to every single page, became a long and expensive process.
CSS Saves a Lot of Work!
The style definitions are normally saved in external .css files.
With an external stylesheet file, you can change the look of an entire website by changing just one file!
Explaination
The <!DOCTYPE html> declaration defines this document to be HTML5
The <html> element is the root element of an HTML page
The <head> element contains meta information about the document
The <title> element specifies a title for the document
The <body> element contains the visible page content
The <h1> element defines a large heading
The <p> element defines a paragraph
HTML Tags
HTML tags are element names surrounded by angle brackets:
- HTML tags normally come in pairs like <p> and </p>
- 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, but with a forward slash inserted before the tag name
The purpose of a web browser (Chrome, IE, Firefox, Safari) is to read HTML documents and display them.
The browser does not display the HTML tags, but uses them to determine how to display the document:
The <!DOCTYPE> Declaration
- The <!DOCTYPE> declaration represents the document type, and helps browsers to display web pages correctly.
- It must only appear once, at the top of the page (before any HTML tags).
- The <!DOCTYPE> declaration is not case sensitive.
HTML Versions
Since the early days of the web, there have been many versions of HTML:
Version Year
HTML 1991
HTML 2.0 1995
HTML 3.2 1997
HTML 4.01 1999
XHTML 2000
HTML5 2014
What is HTML?
HTML is the standard markup language for creating Web pages.
- HTML stands for Hyper Text Markup Language
- HTML describes the structure of Web pages using markup
- HTML elements are the building blocks of HTML pages
- HTML elements are represented by tags
- HTML tags label pieces of content such as "heading", "paragraph", "table", and so on
- Browsers do not display the HTML tags, but use them to render the content of the page
Example:
<!DOCTYPE html>
<html>
<head>
<title>Page Title</title>
</head>
<body>
<h1>My First Heading</h1>
<p>My first paragraph.</p>
</body>
</html>
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