To do CSS problems encountered in the question

What elements are selected by the 19.$ ("Div#intro. Head") selector?
Your answer: id= all elements of class= "head" in the first DIV element of "Intro"

Is 20.jQuery a standard?
Your answer: Yes
Correct answer: No

2.jQuery use CSS selectors to select elements?
Your answer: the error
Correct answer: Correct

The 7.jQuery HTML () method works with HTML and XML documents.
Your answer: correct
Correct answer: Error

12. Which of the following jQuery methods is used to perform asynchronous HTTP requests?
Your answer: Jquery.ajax ()

$ ("#p1"). CSS ("Color", "red"). Slideup (+). Slidedown (2000);
On the chain call is not very understand Ah, in the design mode, read, and then slowly study it

There are several examples of jquery that you like more

Don't know when you can do your own animation ha

To do CSS problems encountered in the question