)
Add all classes specified in iterable to element.
add and addAll are the Dart equivalent of jQuery's addClass.
Each element of iterable must be a valid 'token' representing a single
class, i.e. a non-empty string containing no whitespace.
Source
/**
* Add all classes specified in [iterable] to element.
*
* [add] and [addAll] are the Dart equivalent of jQuery's
* [addClass](http://api.jquery.com/addClass/).
*
* Each element of [iterable] must be a valid 'token' representing a single
* class, i.e. a non-empty string containing no whitespace.
*/
void addAll(Iterable<String> iterable);