Question

According to jQuery load() method api:

.load( url [, data] [, complete(responseText, textStatus, XMLHttpRequest)] )

1. 1st parameter is url
2. 2nd parameter is map or string that is sent to the server
3. 3rd parameter is callback function.

With the working example below

$('#result').load('ajax/test.html', function() {
  alert('Load was performed.');
});

it supplies arguments of ‘url’ and ‘callback function’, [data] argument is skipped.

Shouldn’t the example code treat the callback function as [data] argument (2nd parameter) ? Because of the order that parameters defined in the API . By following the API, 1st is url, 2nd is data, 3rd is callback.

I don’t get why the code would work. Very confused.

Answer 1

It is very clearly written in the jQuery source code.

https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.js

Search for load: function( url, params, callback )

It checks for the params (second parameter) and if it exist, It will call the isFunction method which internally check the type of the argument and return true if it is a function. The rest you know….

This is how isFunction looks like