Question

In this video there is a snippet of code that goes something like this:

if (jQuery) {jQuery(function() {
    // ...
})}

I’ve never seen the jQuery() function before (then again, I’m not a savvy jQuery user), what does it do? Does it ship by default with jQuery or is it specific to IxEdit? Since the usual $(window).load() snippet is missing and the code is somewhat similar I’m guessing it’s a shortcut / alias to:

$(window).load(function() {
    // ...
)}

Am I right? Also what is that jQuery variable? What does it hold? And why is he checking it?

Answer 1

$() is an alias for jQuery(), defined as:

// Expose jQuery to the global object
window.jQuery = window.$ = jQuery;

http://code.jquery.com/jquery-1.4.js

there is a special case defined when $() or jQuery() is called with the first argument being a function:

// HANDLE: $(function)
// Shortcut for document ready
} else if ( jQuery.isFunction( selector ) ) {
    return rootjQuery.ready( selector );
}

sometimes $ can conflict with other libraries (like prototype) that define the same function, so if you call

jQuery.noConflict();

it will remove the $ alias, setting it back to the original value found, essentially:

window.$ = _$;