Your snippet of code looks like it’s referencing methods from one of the popular JavaScript libraries (jQuery, ProtoType, mooTools, and so on).
There’s nothing mysterious about the use of $
in JavaScript. $
is simply a valid JavaScript identifier.
JavaScript allows upper and lower letters, numbers, and $
and _
. The $
was intended to be used for machine-generated variables (such as $0001
).
Prototype, jQuery, and most javascript libraries use the $
as the primary base object (or function). Most of them also have a way to relinquish the $
so that it can be used with another library that uses it. In that case you use jQuery
instead of $
. In fact, $
is just a shortcut for jQuery
.