Why is jQuery.ajax() Calling my Objects Functions?

Question

I'm having an issue where jQuery.ajax() is calling my data objects functions. For example, I have an object structure similar to the following:

var TestFactory = (function () {
    var _id;
    var _attributes;

    return {
        createObject: function (objectId) {
            var value = null;
            _id = objectId;
            _attributes = {};

            function _showErrorStatus() {
                $('label')
                    .css('background-color', 'red')
                    .css('color', 'black')
                    .text('jQuery called me...');
            }

            function _attr(key, value) {
                if (value == null) {
                    return _attributes[key];
                }

                _attributes[key] = value;

                return this;
            }

            return {
                id: _id,
                attributes: _attributes,
                showErrorStatus: _showErrorStatus,
                attr: _attr,                
            }
        }
    }
})();

I'd like to use this object as the data value for my jQuery.ajax() call, as follows:

var myObject = TestFactory.createObject(12345);

myObject.attr('name', 'Fred Flinstone');

$.ajax({
    url: '/echo/json/',
    type: 'GET',
    data: myObject,
    dataType: 'json',
});

The issue I'm running into is jQuery.ajax() is calling the showErrorStatus() function from the object returned by the factory --nowhere in my code do I call this function.

I like the OOP qualities I get out of using this object, so is there any way to handle this case without a significant rewrite (e.g., dropping all my functionality from the "class")?

NOTE: I found it difficult to explain this problem, so here is a complete running example on jsfiddle.

Answer 1

Use JSON.stringify (not a jQuery method).

$.ajax({
    url: '/echo/json/',
    type: 'GET',
    data: JSON.stringify(myObject),
    dataType: 'json',
});

http://jsfiddle.net/HJ9AS/10/

Answer 2

It happens because it's a feature, though not documented as far as I can tell.

If you pass an object, then it assumes you want it to call any functions that are values of object properties.