Jquery objectifying css objects


I'm having a hard time figuring out when you would use $("css object") vs $("#css object")
For example, why do we use "active" instead of ".active" in this course?


Replace this line with your code.


We use "active" when it is already known to be a class name, such as,

`.addClass()`, `.removeClass()` and `.toggleClass()`

Clearly, we do not need to tell jQuery that it is a class name. That's what it is expecting.

In a selector things are different. If we do not denote a class or id, it will look like a type selector.


are all element type selectors. If we wrote,


jQuery would be looking for an <active></active> element, which does not exist in HTML. When we write,


jQuery knows it is looking for a class="active" attribute in the DOM tree.

Starting to make sense?



+++++ addClass removeClass

Every HTML-Element has so called attributes.
One of the possible attributes, is the class-attribute.

If you write the HTML-document, you add the class-attribute
within the Element-Tag by using the syntax
class-keyword = then a string
containing the class-name
OR mutliple class-names which are =separated=from=eachother= by a space

Thus with

 <div class="myClass1 myClass2 myClass3" ></div>

you now have a DIV-Element carrying 3 classes myClass1, myClass2 and myClass3

As part of its CSS-category-of-Methods jQuery gives you the ability
to manipulate this class-attribute
by providing the addClass()-, removeClass()-, toggleClass()-Methods.
You will have to provide the Method at least 1 argument
which is the string VALUE of the class-name.
Thus you have to use

The confusion when to use a pre-pending dot or NOT...
In the Cascading Style Sheet syntax,
you have to prepend-a-dot to the classname
so the CSS will interpret it as a class-attribute
So in the file style.css you will find an object
identified by .active,
In this .active object
the background property-key is set to a particular VALUE


google search
class site:jquery.com
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