Opacity

The   property is used in CSS and certain HTML elements. This property specifies the transparency of an element (the degree to which the background behind the element is overlaid).

Values

 * - A number from  to  . Any value smaller or larger will be clamped to this range.
 * - The element is fully transparent (invisible).
 * - The element is translucent (background can be seen).
 * - The element is fully opaque (solid).

HTML examples:

  Check out the transparency of this box.

  Check out the transparency of this box.

  Check out the transparency of this box.

CSS  example:

pre { opacity:0.5; }