Showing posts with label CSS. Show all posts
Showing posts with label CSS. Show all posts

Wednesday, October 24, 2012

CSS Sheats


Chapter 8


Multiple Style Sheets

If some properties have been set for the same selector in different style sheets, the values will be inherited from the more specific style sheet. 
For example, an external style sheet has these properties for the h3 selector:
h3
{
color:red;
text-align:left;
font-size:8pt;
}
And an internal style sheet has these properties for the h3 selector:
h3
{
text-align:right;
font-size:20pt;
}
If the page with the internal style sheet also links to the external style sheet the properties for h3 will be:
color:red;
text-align:right;
font-size:20pt;
The color is inherited from the external style sheet and the text-alignment and the font-size is replaced by the internal style sheet.

Multiple Styles Will Cascade into One

Styles can be specified:
  • inside an HTML element
  • inside the head section of an HTML page
  • in an external CSS file
Tip: Even multiple external style sheets can be referenced inside a single HTML document.

Cascading order

What style will be used when there is more than one style specified for an HTML element?
Generally speaking we can say that all the styles will "cascade" into a new "virtual" style sheet by the following rules, where number four has the highest priority:
1.    Browser default
2.    External style sheet
3.    Internal style sheet (in the head section)
4.    Inline style (inside an HTML element)
So, an inline style (inside an HTML element) has the highest priority, which means that it will override a style defined inside the <head> tag, or in an external style sheet, or in a browser (a default value).

CSS Sheats



Chapter 7

Three Ways to Insert CSS
There are three ways of inserting a style sheet:
  • 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, you 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:

E-g:

<head>
<link rel="stylesheet" type="text/css" href="mystyle.css" />
</head>
Internal Style Sheet
An internal style sheet should be used when a single document has a unique style. You define internal styles in the head section of an HTML page, by using the <style> tag, like this:

E-g:

<head>
<style>
hr {color:sienna;}
p {margin-left:20px;}
body {background-image:url("images/back40.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:

E-g:

<p style="color:sienna;margin-left:20px">This is a paragraph.</p>

CSS Class Selector


Chapter 6

The class Selector

The class selector is used to specify a style for a group of elements. Unlike the id selector, the class selector is most often used on several elements.
This allows you to set a particular style for many HTML elements with the same class.
The class selector uses the HTML class attribute, and is defined with a "."
In the example below, all HTML elements with class="center" will be center-aligned:

Example :4

<!By using class selector >

<html>
<head>
<style>
.center
{
text-align:center;
}
</style>
</head>

<body>
<h1 class="center">Center-aligned heading</h1>
<p class="center">Center-aligned paragraph.</p>
</body>
</html>

Output is:

Center-aligned heading

Center-aligned paragraph.

CSS Id


Chapter 5

The id and class Selectors

In addition to setting a style for a HTML element, CSS allows you to specify your own selectors called "id" and "class".



The id Selector

The id selector is used to specify a style for a single, unique element.
The id selector uses the id attribute of the HTML element, and is defined with a "#".
The style rule below will be applied to the element with id="para1":

Example :3

<!By using ID >

<html>
<head>
<style>
#para1
{
text-align:center;
color:red;
}
</style>
</head>
<body>
<p id="para1">Hello World!</p>
<p>This paragraph is not affected by the style.</p>
</body>
</html>

Output is:

Hello World!
This paragraph is not affected by the style.


CSS Link




Chapter 4



Example :2

<html>
<head>
<style>
body {background-color:tan;}
h1   {color:maroon;font-size:20pt;}
hr   {color:navy;}
p    {font-size:11pt;margin-left:15px;}
a:link    {color:green;}
a:visited {color:yellow;}
a:hover   {color:black;}
a:active  {color:blue;}
</style>
</head>

<body>

<h1>This is a header 1</h1>
<hr>

<p>You can see that the style
sheet formats the text</p>

<p><a href="http://atoz4tutorials.blogspot.in/"
target="_blank">This is a link</a></p>

</body>
</html>

Output is:

This is a header 1

You can see that the style sheet formats the text


CSS Head



Chapter 3



Example :1

<head>
<style>
body {background-color:yellow;}
h1   {font-size:36pt;}
h2   {color:blue;}
p    {margin-left:50px;}
</style>
</head>

<body>

<h1>This header is 36 pt</h1>
<h2>This header is blue</h2>

<p>This paragraph has a left margin of 50 pixels</p>

</body>
</html>

Output is:

This header is 36 pt

This header is blue

This paragraph has a left margin of 50 pixels

CSS Syntax


Chapter 2


CSS Syntax

A CSS rule has two main parts: a selector, and one or more declarations:




The selector is normally the HTML element you want to style.
Each declaration consists of a property and a value.
The property is the style attribute you want to change. Each property has a value.

CSS Introducation


Chapter 1



CSS


What You Should Already Know
Before you continue you should have a basic understanding HTML.

What is What You Should Already Know
Before you continue you should have a basic understanding of the following:
  • HTML

What is CSS?
  • CSS stands for Cascading Style Sheets
  • Styles define how to display HTML elements
  • Styles were added to HTML 4.0 to solve a problem
  • External Style Sheets can save a lot of work
  • External Style Sheets are stored in CSS files


Styles Solved a Big Problem
HTML was never intended to contain tags for formatting a document.
HTML was intended to define the content of a document, 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 web sites, where fonts and color information were added to every single page, became a long and expensive process.

To solve this problem, the World Wide Web Consortium created CSS.
In HTML , all formatting could be removed from the HTML document, and stored in a separate CSS file.
All browsers support CSS today.


CSS Saves a Lot of Work!
CSS defines HOW HTML elements are to be displayed.
Styles are normally saved in external .css files. External style sheets enable you to change the appearance and layout of all the pages in a Web site, just by editing one single file!