How is the transparency of Css:box-shadow set?

Today we found that using the Box-shadow property, you can add a shadow effect to p, but add the effect if:

-moz-box-shadow:0 4px 4px #999; -webkit-box-shadow:0 4px 4px #999; box-shadow:0 4px 4px #999;

The color set using # is not transparent. This sets the color of the shadow, if the shadow falls in a position that is not white, or even dynamic, such as falling on a slide, several different color pictures are carousel. So setting the color of the shadow will be the shadow effect looks very fake!

WORKAROUND: Use RGBA instead.

-moz-box-shadow:0 4px 4px rgba (0, 0, 0, 0.4); -webkit-box-shadow:0 4px 4px rgba (0, 0, 0, 0.4); box-shadow:0 4px 4px rgba (0, 0, 0, 0.4);

Here to explain:

IE6 and IE7 should not support the Box-shadow property.

Can be used: *filter:progid:dximagetransform.microsoft.shadow (strength=4, direction=135, color= "#888888"); To replace

Because the shadows I set are not necessarily required to be displayed in all browsers. So I did not add this line of code, so there is no validation here will be color= "#888888" in the color with RGBA to replace whether it is feasible, the need for friends to verify their own, estimated to be too tough!

My principles:

As long as it is not layout dislocation and other issues, I will not do compatibility changes.

In order to reduce the number of browsers do not upgrade the stubborn, there is no need to add a line of redundant code, since the use of the old version of the browser, that the effect is not beautiful enough to see is certain.

The reason why a lot of old version of IE browser to exist now, are front-end accustomed to!