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

C H A P T E R 10
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Extending jQuery
jQuery’s easy-to-use syntax led developers to begin writing scripts to achieve custom effects and other
tasks. To make these scripts configurable and reusable, these developers constructed these scripts as
plugins, or scripts that extend jQuery by adding new methods to the library. In this chapter, you’ll learn
how to add your own plugins to jQuery.
Adding Functions to jQuery
In some cases, it may be desirable to add a function directly to the jQuery object, which means you
would be able to call it like so:
$.yourFunction();
Adding functions to jQuery can help you keep your scripts organized and ensure that your function
calls follow a consistent format. However, it’s important to note that adding a function to jQuery does
not allow you to chain it with a set of selected DOM elements; for this, you must use a method, which
you’ll learn how to do in this chapter.
Adding Your Date Validation Function to jQuery
In your first extending jQuery example, you will add the date validation function you wrote in the last
chapter to the jQuery object. Specifically, you’ll leverage valid-date.js.
Allowing Custom Aliases in jQuery Plugins
One thing you should consider is allowing custom aliases in your jQuery plugins. While this isn’t strictly
necessary, it is strongly encouraged because it can help you keep your plugin from breaking if the $
shortcut is given up by jQuery.noConflict(). Better still, this feature is so simple to implement that it’s
actually a little silly not to include it.
When building a new plugin, you should put the plugin code within a function that is executed
immediately when the script is loaded. At its outset, the script should look like this:
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