How to change placeholder color on focus?

Question

How to change the color of placeholder when focus the input field? I use this css to set the default color, but how to change it on focus?

::-webkit-input-placeholder { color: #999; }

/* Firefox < 19 */
:-moz-placeholder { color: #999; }

/* Firefox > 19 */
::-moz-placeholder { color: #999; }

/* Internet Explorer 10 */
:-ms-input-placeholder { color: #999; }

Answer 1

Try this, this should work :

input::-webkit-input-placeholder {
    color: #999;
}
input:focus::-webkit-input-placeholder {
    color: red;
}

/* Firefox < 19 */
input:-moz-placeholder {
    color: #999;
}
input:focus:-moz-placeholder {
    color: red;
}

/* Firefox > 19 */
input::-moz-placeholder {
    color: #999;
}
input:focus::-moz-placeholder {
    color: red;
}

/* Internet Explorer 10 */
input:-ms-input-placeholder {
    color: #999;
}
input:focus:-ms-input-placeholder {
    color: red;
}

Here is an example : http://jsfiddle.net/XDutj/27/