CSS3 :read-only Selector
Select and style only if the input element is "readonly":
Definition and Usage
The :read-only selector selects elements which are "readonly".
Form elements with a "readonly" attribute are defined as "readonly".
Note: Currently, in most browsers, the :read-only selector only applies to input and textarea elements, but it should apply to all elements which are "readonly".
The :read-only selector is supported in Chrome, Safari and Opera.
Internet Explorer does not support the :read-only selector.
Firefox supports an alternative, the :-moz-read-only selector.
CSS Selector :read-write