How does this syntax work ?
Does it add "data" and "something" both ?
Does it not need to be added separately ?
If we can ad teo elements in one statement, then can we add three elements in one statement ?
Whatever "doc" may be, the addElement() method returns "this", that is a reference to the doc object itself. Why? To enable the kind of syntax you posted here, which can, at times, be convenient. It's called the Method Chaining pattern.
firstly doc is in object.after applying the method addElement() on it .it returns an object(may be it is object of the type of doc)..on which by chaining rule again the addElement()method is applied..and now it adds 'something' to it..clear or not??