Harvard Extension School
CSCI E-12 Fundamentals of Web Site Development | Spring 2019

## Opacity - RGBA - red, green, blue, alpha

A = alpha channel, used for opacity.
Values of 0 to 1, where 0 is fully transparent, 1 is fully opaque

Example 6.19 - CSS3 text-shadow - Example 6.19 (Without Styles) | <div class="opacity-demo"><p style="color: rgba(0,0,0,1)">Opacity of 1</p><p style="color: rgba(0,0,0,0.75)">Opacity of 0.75</p><p style="color: rgba(0,0,0,0.5)">Opacity of 0.5</p><p style="color: rgba(0,0,0,0.25)">Opacity of 0.25</p><p style="color: rgba(0,0,0,0)">Opacity of 0</p></div>.opacity-demo { background-image: url('http://cscie12.dce.harvard.edu/resources/images/satin.png'); color: white; } .opacity-demo p { font-size: 200%; font-weight: bold; font-family: helvetica,sans-serif;}

- Markup
- Style
- Display
- Screenshot

    <div class="opacity-demo"><p style="color: rgba(0,0,0,1)">Opacity of 1</p>
    <p style="color: rgba(0,0,0,0.75)">Opacity of 0.75</p>
    <p style="color: rgba(0,0,0,0.5)">Opacity of 0.5</p>
    <p style="color: rgba(0,0,0,0.25)">Opacity of 0.25</p>
    <p style="color: rgba(0,0,0,0)">Opacity of 0</p>
    </div>

In `style` element (`<style type="text/css">`) within `head` element:

    .opacity-demo {
      background-image: url('images/satin.png');
      color: white;
    }
    .opacity-demo p { font-size: 200%; font-weight: bold; font-family: helvetica,sans-serif;}

Opacity of 1

Opacity of 0.75

Opacity of 0.5

Opacity of 0.25

Opacity of 0

Copyright © David Heitmeyer