How can I set border-opacity for IE?

Question

The following code works for chrome and firefox, however it doesn't work in IE.

border: 2px solid rgb(191, 191, 191, .25);

How can I mimic this effect for IE?

Answer 1

missing alpha channel

border:2px solid rgba(191, 191, 191, .25)

Answer 2

Use rgba instead of rgb

border: 2px solid rgba(191, 191, 191, .25);