CSS for Beginners

by DHANESH.T.S CSS

What is Cascading Style Sheets (CSS) is a simple mechanism for adding style (e.g. fonts, colors, spacing) to Web documents. PUNE IT LABS

Advantages of CSS

Completely consistent with the look and feel of your pages

More control over the layout and design

Pages download faster, sometimes by as much as 50%

You have to type less code, and your pages are shorter and neater.

CSS properties can also be dynamically changed with a JavaScript.

eg. object .style.cssFloat="left"

PUNE IT LABS

. With a combination of positioning, floating, margins, padding and borders, you should be able to represent ANY web design and there is nothing that can be done in tables that can not be done with CSS.

PUNE IT LABS

There are three parts to CSS

The styles

a blue headline

eg: <font color="#0000ff"><h4>a blue headline</h4></font>

a blue headline

Their placement

The fact that they can cascade.

PUNE IT LABS

Where HTML has tags, CSS has 'selectors'.

A Cascading Style Sheets rule is made up of a selector and a declaration.

H2 {color: blue;}

selector {declaration;}

The declaration is the part of the rule inside the curly braces. It specifies what a style effect will be. For example, "color: blue".

Eg: body { font-size: 12px; color: navy; }

PUNE IT LABS

A declaration has two parts separated by a colon: property and value.

selector {property:value}

More than one declaration may be placed inside the curly braces

A semi-colon must separate each declaration from the next. The ending declaration does not require a semi-colon

Eg. selector {property:value; property:value;}

H2 {color:blue; font-family:Arial, sans-serif;}

If you neglect to place a semi-colon between any two declarations your style sheet will totally fail.

H1 {font-family:Arial, Helvetica, sans-serif;} H2 {font-family:Arial, Helvetica, sans-serif;} H3 {font-family:Arial, Helvetica, sans-serif;}

H1, H2, H3 {font-family:Arial, Helvetica, sans-serif;}

PUNE IT LABS

In-line

Internal

External

Applying CSS PUNE IT LABS

<p style="color: red">Sample text</p>

In-line

HTML should be a presentation free document, and so in-line styles should be

avoided wherever possible.

PUNE IT LABS

<html> <head> <title>CSS Example</title> <style type="text/css"> p { color: red; }

a { color: blue; } </style> .......

Internal PUNE IT LABS

p { color: red; }

a { color: blue; }

<html> <head> <title>CSS Example</title> <link rel="stylesheet" type="text/css" href="web.css" /> ... External PUNE IT LABS

Lengths and Percentages

There are specific units for values used in CSS, but there are some general units that are used in a number of properties

Such as-

em (such as font-size: 2em)

ex (one ex is the x-height of a font (x-height is usually about half the font-size)

px (such as font-size: 12px) pixels

pt (such as font-size: 12pt) point (1 pt is the same as 1/72 inch)

pc pica (1 pc is the same as 12 points)

% (such as font-size: 80%)percentage

Other units include cm (centimetres), mm (millimetres) and in (inches).

When a value is zero , you do not need to state a unit.

Eg:

border : 0

PUNE IT LABS

Different foms:

Name of Colour

RGB

HEX code

CSS brings 16 million colours to Web Page.

There are 17 valid predefined colour names.

They are - aqua, black, blue, fuchsia, gray, green, lime, maroon, navy, olive, orange, purple, red, silver, teal, white, and yellow.

PUNE IT LABS

red

rgb(255,0,0)

rgb(100%,0%,0%)

#ff0000

#f00

transparent is also a valid value.

The three values in the rbg value are from 0 to 255.

Hexadecimal is a base-16 number system. hexadecimal has 16 digits, from 0 to f.

The hex number is prefixed with a hash character ( # ) and can be three or six digits in length.

Basically, the three-digit version is a compressed version of the six-digit (#f00 becomes #ff0000, #c96 becomes #cc9966 etc.).

PUNE IT LABS

None : The element will not be displayed.

p {display : none}

Block : The element will be displayed as a block-level element, with a line break before and after the element.

p {display : block}

Inline : The element will be displayed as an inline element, with no line break before or after the element.

p {display : inline}

PUNE IT LABS

Other display types

ol

ul

PUNE IT LABS

Static

Relative

Absolute

Fixed

PUNE IT LABS

Static: The value static is the default value for elements and renders the position in the normal order of things as they appear in the html

Relative: It is much like static, but the element can be offset from its original position with the properties top , right , bottom and left .

Absolute: The absolute element can be placed anywhere on the page using top , right , bottom and left .

Fixed: It behaves like absolute, but fixed elements should stay exactly where they are on the screen even when the page is scrolled.

PUNE IT LABS

Floating an element will shift it to the right or left of a line, with surrounding content flowing around it.

Floating is normally used to position smaller elements within a page

Eg:

img { float: left }

PUNE IT LABS

Clear:

The CSS clear property is used to for control flow when using the float property. Using CSS clear, you can specify whether to keep one or both sides of an element "clear" (i.e. no elements can appear on the side that is clear).

none - floating elements can appear on either side

left - floating elements can not appear on the left (i.e. keep the left side "clear")

right - floating elements can not appear on the right (i.e. keep the right side "clear")

both - floating elements can not appear on the left or right (i.e. keep both sides "clear")

inherit

PUNE IT LABS

Font-family

The font you specify must be on the user's computer, so there is little point in using obscure fonts.

The most commonly used are arial, verdana and times new roman), but you can specify more than one font, separated by commas .

If the name of the font is more than one word it should be put in quotation marks (“------“)

Font-size

The size of the font. Be careful with this - text such as headings should not just be a paragraph in a large font; you should still use headings ( h1 , h2 etc.)

PUNE IT LABS