How to detect what Library is behind the $ function?

Question

I am developing some JavaScript that should work with either Prototype.js or JQuery, thus I need some way to identify what is the primary library in use. How can I do that?

Answer 1

You can check for jQuery like this:

if (window.$ === window.jQuery)

Answer 2

Well, you could check for the presence of jQuery:

if(window.jQuery !== "undefined")
{
    // jQuery Yay!
}

and then if it is assigned to $

if(window.jQuery === window.$)
{
    // jQuery Yay!
}