The opacity property sets the opacity level for an element, opacity allows to change the transparency of an element.

- Syntax:
opacity: X;
- X - represents a value between 0 (completely transparent) and 1.0 (no transparency).

CSS opacity examples

1) Example, a <div> with a css transparency of 40%:
<style>
#dv {
 background-color:#babafe;
 width:200px;
 height:100px;
 opacity:0.4;
}
</style>

<h4>Example opacity 40%</h4>

<div id='dv'>Some content ...</div>
2) Example, sets opacity 50% to an image:
<style>
#im {
 opacity:0.5;
}
</style>

<h4>Example opacity 50% on image</h4>

<img src='css/html_course.jpg' alt='HTML and CSS Course' width='155' height='160' id='im' />
3) Example, effect image transparency 50%, to 100% on the hover state:
<style>
#im2 {
 opacity:0.5;
}
#im2:hover {
 opacity:1;
}
</style>

<h4>Example changing transparency on hover</h4>
<p>Place the mouse over the image below.</p>

<img src='css/html_course.jpg' alt='HTML and CSS Course' width='155' height='160' id='im2' />
4) DIV content that is covered with a transparent box on mouseover (the transparent box [a <div>] must be empty and set with   position:absolute;):
<style>
#trans {
 display:none;
 position:absolute;
 top:2%;
 left:2%;
 width:96%;
 height:95%;
 background-color:#07fe08;
 opacity:0.5;
}
#cnt {
 position:relative;
 background:#e7e8fe;
 width:300px;
 height:200px;
 border:1px solid blue;
 padding:20px;
}
#cnt:hover #trans { display:block; }
</style>

<h4>Example content hovered with transparency element on hover</h4>

<div id='cnt'>
 <div id='trans'></div>
 Place the mouse over this box to see the opacity effect.
<img src='css/css3.jpg' alt='CSS3 opacity' width='160' height='98' />
</div>

Daily Test with Code Example

HTML
CSS
JavaScript
PHP-MySQL
Which HTML5 tag can be used to embed an external application (SWF, PDF) in web page?
<mark> <embed> <canvas>
<embed src="flash_game.swf" width="450" height="350" />
Which CSS pseudo-element adds a special style to the first line of a text?
:first-letter :before :first-line
#id:first-line {
  font-weight: bold;
  color: blue;
}
Click on the window object property which gets or sets the URL of current page.
window.location window.self window.status
var url = window.location;
alert(url);
Indicate the PHP function used to get the contents of a file or page and store it into a string.
fopen() file_put_contents() file_get_contents()
$homepage = file_get_contents("http://coursesweb.net/");
echo $homepage;
CSS3 opacity

Last accessed pages

  1. Node.js Move and Copy file (18986)
  2. GraidleChart Create Graphic Charts (1464)
  3. Multiple Select Dropdown List with JavaScript (10171)
  4. Dynamic variables in JavaScript (13671)
  5. Node.js Working with files (461)

Popular pages this month

  1. Courses Web: PHP-MySQL JavaScript Node.js Ajax HTML CSS (320)
  2. Register and show online users and visitors (215)
  3. Node.js Move and Copy file (174)
  4. Read Excel file data in PHP - PhpExcelReader (159)
  5. PHP-MySQL free course, online tutorials PHP MySQL code (156)