EXCITING STUDY: CSS Background

Tuesday, November 22, 2011

CSS Background

CSS background properties are used to define the background effects of an element.

CSS properties used for background effects:

background-color
background-image
background-repeat
background-attachment
background-position

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:

Example

body {background-color:#b0c4de;}

The background color can be specified by:

name - a color name, like "red"
RGB - an RGB value, like "rgb(255,0,0)"
Hex - a hex value, like "#ff0000"

In the example below, the h1, p, and div elements have different background colors:

Example

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:

Example

body {background-image:url('paper.gif');}

Below is an example of a bad combination of text and background image. The text is almost not readable:

Example

body {background-image:url('bgdesert.jpg');}

Background Image - Repeat Horizontally or Vertically

By default, the background-image property repeats an image both horizontally and vertically.
Some images should be repeated only horizontally or vertically, or they will look strange, like this:

Example

body
{
background-image:url('gradient2.png');
}

If the image is repeated only horizontally (repeat-x), the background will look better:

Example

body
{
background-image:url('gradient2.png');
background-repeat:repeat-x;
}

Background Image - Set position and no-repeat

When using a background image, use an image that does not disturb the text.
Showing the image only once is specified by the background-repeat property:

Example

body
{
background-image:url('img_tree.png');
background-repeat:no-repeat;
}

In the example above, the background image is shown in the same place as the text. We want to change the position of the image, so that it does not disturb the text too much.
The position of the image is specified by the background-position property:

Example

body
{
background-image:url('img_tree.png');
background-repeat:no-repeat;
background-position:right top;
}

Background - Shorthand property

As you can see from the examples above, there are many properties to consider when dealing with backgrounds.
To shorten the code, it is also possible to specify all the properties in one single property. This is called a shorthand property.
The shorthand property for background is simply "background":

Example

body {background:#ffffff url('img_tree.png') no-repeat right top;}

When using the shorthand property the order of the property values are:

background-color
background-image
background-repeat
background-attachment
background-position

It does not matter if one of the property values is missing, as long as the ones that are present are in this order.
This example uses more advanced CSS.

More Examples

How to set a fixed background image
This example demonstrates how to set a fixed background image. The image will not scroll with the rest of the page.

All CSS Background Properties

The number in the "CSS" column indicates in which CSS version the property is defined (CSS1 or CSS2).

Property	Description	Values	CSS
background	Sets all the background properties in one declaration	background-color background-image background-repeat background-attachment background-position inherit	1
background-attachment	Sets whether a background image is fixed or scrolls with the rest of the page	scroll fixed inherit	1
background-color	Sets the background color of an element	color-rgb color-hex color-name transparent inherit	1
background-image	Sets the background image for an element	url(URL) none inherit	1
background-position	Sets the starting position of a background image	left top left center left bottom right top right center right bottom center top center center center bottom x% y% xpos ypos inherit	1
background-repeat	Sets if/how a background image will be repeated	repeat repeat-x repeat-y no-repeat inherit	1