+ return $value;
+ }
+
+
+ /**
+ * Pick apart some CSS and check it for forbidden or unsafe structures.
+ * Returns a sanitized string. This sanitized string will have
+ * character references and escape sequences decoded and comments
+ * stripped (unless it is itself one valid comment, in which case the value
+ * will be passed through). If the input is just too evil, only a comment
+ * complaining about evilness will be returned.
+ *
+ * Currently URL references, 'expression', 'tps' are forbidden.
+ *
+ * NOTE: Despite the fact that character references are decoded, the
+ * returned string may contain character references given certain
+ * clever input strings. These character references must
+ * be escaped before the return value is embedded in HTML.
+ *
+ * @param string $value
+ * @return string
+ */
+ static function checkCss( $value ) {
+ $value = self::normalizeCss( $value );
+