The StyleSheet.disabled property indicates whether the style sheet is prevented from applying to the document. A style sheet may be disabled by manually setting this property to true or if it's an inactive alternative style sheet. Note that disabled == false does not guarantee the style sheet is applied (it could be removed from the document, for instance).
Syntax
bool = stylesheet.disabled
Example
// if the stylesheet is disabled...
if (stylesheet.disabled) {
// apply style in-line
}