I was surprised that this didn't work in Firefox (try it on Chrome and Firefox: http://jsfiddle.net/YzkSx/):
<!doctype html>
<html>
<head>
<title>Placeholder demo</title>
<style type="text/css">
input {color: red}
</style>
</head>
<body>
<input id="test" placeholder="Placeholder text!">
</body>
</html>
Because I apply a red color to the input, the placeholder ends up being red as well. In Chrome and Safari, if I 'color' the input, the placeholder is not affected.
I know about the :moz-placeholder pseudo-class, but it seems like I shouldn't have to bother with that if all I want is a different color applied to the input when a user starts typing.
Thanks for your help!