Pro PHP and jQuery by Jason Lengstorf.pdf - Computer Science ...

Only one paragraph in our document has an id of "bar", as we see in the result:
>>> $("#bar");
[ p#bar ]
Combining Selectors for More-Precise Selection
CHAPTER 1 ■ INTRODUCING JQUERY
In some situations, it may be necessary to isolate only certain tags that correspond to a class, which is
easy to do by combining tag type and class in your selector.
Enter the following in the console to select only paragraph tags with the class foo:
$("p.foo");
The results in the console confirm that the span was ignored, even though it has the class foo:
>>> $("p.foo");
[p.foo]
Using Multiple Selectors
In the event that you need to access multiple elements, multiple selectors can be used to access all of
those elements at once. For instance, if you wanted to select any paragraph tag with a class of foo or any
element with an ID of bar, you would use the following:
$("p.foo,#bar");
This returns elements that match at least one selector specified in |the string:
>>> $("p.foo,#bar");
[ p.foo, p#bar ]
Hierarchy Selectors
Sometimes, it’s not enough to be able to select by element, class, or ID. There are points at which you’ll
need to access elements contained within, next to, or after another element, such as removing an active
class from all menu items except the one that was just clicked, grabbing all the list items out of the
selected unordered list, or changing attributes on the wrapper element when a form item is selected.
Selecting Descendant Elements
Selecting descendant elements, which are elements contained within other elements, is done using the
ancestor selector followed by a space and the descendant selector.
ancestor descendent
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