Pages

1/16/2019

CSS Backgrounds

The CSS background properties are used to define the background effects for elements.
CSS background properties:
  • 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 set like this:

Example

body {
  background-color: lightblue;
}
With CSS, a color is most often specified by:
  • a valid color name - like "red"
  • a HEX value - like "#ff0000"
  • an RGB value - like "rgb(255,0,0)"
Look at CSS Color Values for a complete list of possible color values.
In the example below, the <h1>, <p>, and <div> elements have different background colors:

Example

h1 {
  background-color: green;
}

div {
  background-color: lightblue;
}

{
  background-color: yellow;
}

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 hardly readable:

Example

body {
  background-image: url("bgdesert.jpg");
}
Note: When using a background image, use an image that does not disturb the text.

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("gradient_bg.png");
}
If the image above is repeated only horizontally (background-repeat: repeat-x;), the background will look better:

Example

body {
  background-image: url("gradient_bg.png");
  background-repeat: repeat-x;
}
Tip: To repeat an image vertically, set background-repeat: repeat-y;

Background Image - Set position and no-repeat

Showing the background image only once is also 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 Image - Fixed position

To specify that the background image should be fixed (will not scroll with the rest of the page), use the background-attachment property:

Example

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

Background - Shorthand property

To shorten the code, it is also possible to specify all the background properties in one single property. This is called a shorthand property.
The shorthand property for background is background:

Example

body {
  background: #ffffff url("img_tree.png") no-repeat right top;
}
When using the shorthand property the order of the property values is:
  • 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 other ones are in this order.

All CSS Background Properties

PropertyDescription
backgroundSets all the background properties in one declaration
background-attachmentSets whether a background image is fixed or scrolls with the rest of the page
background-clipSpecifies the painting area of the background
background-colorSets the background color of an element
background-imageSets the background image for an element
background-originSpecifies where the background image(s) is/are positioned
background-positionSets the starting position of a background image
background-repeatSets how a background image will be repeated
background-sizeSpecifies the size of the background image(s)


Read More »

HTML Colors

HTML colors are specified using predefined color names, or RGB, HEX, HSL, RGBA, HSLA values.

Color Names

In HTML, a color can be specified by using a color name:
Tomato
Orange
DodgerBlue
MediumSeaGreen
Gray
SlateBlue
Violet
LightGray






















Background Color

You can set the background color for HTML elements:
Hello World


Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat. Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

Example

<h1 style="background-color:DodgerBlue;">Hello World</h1>
<p style="background-color:Tomato;">Lorem ipsum...</p>


Text Color

You can set the color of text:

Hello World

Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut laoreet dolore magna aliquam erat volutpat.
Ut wisi enim ad minim veniam, quis nostrud exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat.

Example

<h1 style="color:Tomato;">Hello World</h1>
<p style="color:DodgerBlue;">Lorem ipsum...</p>
<p style="color:MediumSeaGreen;">Ut wisi enim...</p>


Border Color

You can set the color of borders:

Hello World

Hello World

Hello World

Example

<h1 style="border:2px solid Tomato;">Hello World</h1>
<h1 style="border:2px solid DodgerBlue;">Hello World</h1>
<h1 style="border:2px solid Violet;">Hello World</h1>


Color Values

In HTML, colors can also be specified using RGB values, HEX values, HSL values, RGBA values, and HSLA values:
Same as color name "Tomato":
rgb(255, 99, 71)
#ff6347
hsl(9, 100%, 64%)
Same as color name "Tomato", but 50% transparent:
rgba(255, 99, 71, 0.5)
hsla(9, 100%, 64%, 0.5)

Example

<h1 style="background-color:rgb(255, 99, 71);">...</h1>
<h1 style="background-color:#ff6347;">...</h1>
<h1 style="background-color:hsl(9, 100%, 64%);">...</h1>

<h1 style="background-color:rgba(255, 99, 71, 0.5);">...</h1>
<h1 style="background-color:hsla(9, 100%, 64%, 0.5);">...</h1>


RGB Value

In HTML, a color can be specified as an RGB value, using this formula:
rgb(red, greenblue)
Each parameter (red, green, and blue) defines the intensity of the color between 0 and 255.
For example, rgb(255, 0, 0) is displayed as red, because red is set to its highest value (255) and the others are set to 0.
To display the color black, all color parameters must be set to 0, like this: rgb(0, 0, 0).
To display the color white, all color parameters must be set to 255, like this: rgb(255, 255, 255).
Experiment by mixing the RGB values below:
rgb(255, 99, 71)



RED

255
GREEN

99
BLUE

71

Example

rgb(255, 0, 0)
rgb(0, 0, 255)
rgb(60, 179, 113)
rgb(238, 130, 238)
rgb(255, 165, 0)
rgb(106, 90, 205)










































Shades of gray are often defined using equal values for all the 3 light sources:

Example

rgb(0, 0, 0)
rgb(60, 60, 60)
rgb(120, 120, 120)
rgb(180, 180, 180)
rgb(240, 240, 240)
rgb(255, 255, 255)































HEX Value

In HTML, a color can be specified using a hexadecimal value in the form:
#rrggbb
Where rr (red), gg (green) and bb (blue) are hexadecimal values between 00 and ff (same as decimal 0-255).
For example, #ff0000 is displayed as red, because red is set to its highest value (ff) and the others are set to the lowest value (00).

Example

#ff0000
#0000ff
#3cb371
#ee82ee
#ffa500
#6a5acd
































Shades of gray are often defined using equal values for all the 3 light sources:

Example

#000000
#3c3c3c
#787878
#b4b4b4
#f0f0f0
#ffffff































HSL Value

In HTML, a color can be specified using hue, saturation, and lightness (HSL) in the form:
hsl(huesaturationlightness)
Hue is a degree on the color wheel from 0 to 360. 0 is red, 120 is green, and 240 is blue.
Saturation is a percentage value, 0% means a shade of gray, and 100% is the full color.
Lightness is also a percentage, 0% is black, 50% is neither light or dark, 100% is white

Example

hsl(0, 100%, 50%)
hsl(240, 100%, 50%)
hsl(147, 50%, 47%)
hsl(300, 76%, 72%)
hsl(39, 100%, 50%)
hsl(248, 53%, 58%)


































Saturation

Saturation can be described as the intensity of a color.
100% is pure color, no shades of gray
50% is 50% gray, but you can still see the color.
0% is completely gray, you can no longer see the color.

Example

hsl(0, 100%, 50%)
hsl(0, 80%, 50%)
hsl(0, 60%, 50%)
hsl(0, 40%, 50%)
hsl(0, 20%, 50%)
hsl(0, 0%, 50%)

































Lightness

The lightness of a color can be described as how much light you want to give the color, where 0% means no light (black), 50% means 50% light (neither dark nor light) 100% means full lightness (white).

Example

hsl(0, 100%, 0%)
hsl(0, 100%, 25%)
hsl(0, 100%, 50%)
hsl(0, 100%, 75%)
hsl(0, 100%, 90%)
hsl(0, 100%, 100%)






























Shades of gray are often defined by setting the hue and saturation to 0, and adjust the lightness from 0% to 100% to get darker/lighter shades:

Example

hsl(0, 0%, 0%)
hsl(0, 0%, 24%)
hsl(0, 0%, 47%)
hsl(0, 0%, 71%)
hsl(0, 0%, 94%)
hsl(0, 0%, 100%)































RGBA Value

RGBA color values are an extension of RGB color values with an alpha channel - which specifies the opacity for a color.
An RGBA color value is specified with:
rgba(red, greenblue, alpha)
The alpha parameter is a number between 0.0 (fully transparent) and 1.0 (not transparent at all):

Example

rgba(255, 99, 71, 0)
rgba(255, 99, 71, 0.2)
rgba(255, 99, 71, 0.4)
rgba(255, 99, 71, 0.6)
rgba(255, 99, 71, 0.8)
rgba(255, 99, 71, 1)

































HSLA Value

HSLA color values are an extension of HSL color values with an alpha channel - which specifies the opacity for a color.
An HSLA color value is specified with:
hsla(hue, saturationlightness, alpha)
The alpha parameter is a number between 0.0 (fully transparent) and 1.0 (not transparent at all):

Example

hsla(9, 100%, 64%, 0)
hsla(9, 100%, 64%, 0.2)
hsla(9, 100%, 64%, 0.4)
hsla(9, 100%, 64%, 0.6)
hsla(9, 100%, 64%, 0.8)
hsla(9, 100%, 64%, 1)







Read More »

1/14/2019

HTML Comments

  • Comment tags are used to insert comments in the HTML source code.



HTML Comment Tags

You can add comments to your HTML source by using the following syntax:
<!-- Write your comments here -->
Notice that there is an exclamation point (!) in the opening tag, but not in the closing tag.
Note: Comments are not displayed by the browser, but they can help document your HTML source code.
With comments you can place notifications and reminders in your HTML:

Example

<!-- This is a comment -->

<p>This is a paragraph.</p>

<!-- Remember to add more information here -->
Try it Yourself »
Comments are also great for debugging HTML, because you can comment out HTML lines of code, one at a time, to search for errors:

Example

<!-- Do not display this at the moment
<img border="0" src="pic_trulli.jpg" alt="Trulli">
-->
Read More »