CSS3 Opacity

Syntax :

E { opacity:number;}

Number : Is in decimal fraction. That is a number between 0.0 and 1.0.

0.0                                                  0.0  is fully transparent and 1.0 is fully opaque.

       Example: 

       CSS :

     

      #opacity {

                                      background-color:black;

                                      height:100px;

                                      width:100px;

                                      opacity:.5;

                             }

       HTML

        <div id="opacity"></div>

       Output:

       Before Opacity : 

       After Opacity : 

How To Create a Circles With CSS3

Thanks to CSS3. You can use a circle using CSS3 with out using any images.

The code goes here...

CSS :

<style>
div {
background-color:rgb(120,250,20);
border:3px solid #333;
height:150px;
width:150px;                                                                Out Put

Circle using CSS3

-webkit-border-radius:75px;
-moz-border-radius:75px;
border-radius:75px;
box-shadow:inset 0 25px 35px #535353;
}
</style>

HTML : 
<div></div>

NOte : 
I used the box-shadow property just to look attractive.