CSS3 Tests: Opacity
A test of the CSS3 Opacity declaration.
Please Note!
This is NOT a test of whether a browser can make elements opaque or not. While IE does not support opacity, it has an alternative way. This just tests the opacity declaration. It needs to be a fraction value (I used .5).
Example
If the below element is opaque your browser supports opacity (duh!). Normally the div has a white background with black text. I added an extra span to test as well at the advice of Chris Lilley.
This is the test element (div).
This is a span inside the div.
Results
Mozilla 1.7 Beta and Safari 1.2 support opacity. Previous Mozilla required -moz-opacity. Internet explorer needs a height and width set for an element and filter: alpha(opacity=50), Safari 1.1 and lower needs -khtml-opacity.