The most basic concept of jQuery is to “select some elements and do something with them.” jQuery supports most CSS3 selectors, as well as some non-standard selectors. For a complete selector reference, visit http://api.jquery.com/category/selectors/.

Following are a few examples of common selection techniques.






Every time you make a selection, a lot of code runs, and jQuery doesn't do caching of selections for you. If you've made a selection that you might need to make again, you should save the selection in a variable rather than making the selection repeatedly.


Note

In Example 3.10, “Storing selections in a variable”, the variable name begins with a dollar sign. Unlike in other languages, there's nothing special about the dollar sign in JavaScript -- it's just another character. We use it here to indicate that the variable contains a jQuery object. This practice -- a sort of Hungarian notation -- is merely convention, and is not mandatory.

Once you've stored your selection, you can call jQuery methods on the variable you stored it in just like you would have called them on the original selection.

Note

A selection only fetches the elements that are on the page when you make the selection. If you add elements to the page later, you'll have to repeat the selection or otherwise add them to the selection stored in the variable. Stored selections don't magically update when the DOM changes.