When changing a button's background color, how do you preserve the "rounded" edges?

[BMAN99]

Hey guys,

I just noticed that when changing the background color of a <button> element, that the button's edges automatically change from rounded to square.

Is there any way to prevent this? (without resorting to having to use an image for the button)

[rtrethewey]

If you want to do it all in CSS, you need to use border-radius... but, of course, older versions of Internet Explorer (before IE9) don't support it.