small event driver programe

AjaxForm

/**
 * @description Ajax Form object. Depend on the jQuery and jquery.form.js
 * @param
 */
function AjaxForm(settings) {
	this.settings = settings;
	this.action = {};
	this.__load(settings.url, settings.form_id);
};

AjaxForm.prototype.__load = function (url, form_id) {
	var This = this;
	$.ajax({
		dataType:'JSON',
		type:'GET',
		url:This.settings.url,
		data:{tpl: This.settings.form_id},
		success: function (response, status) {
			// Fire event listener
			This.emmit('loaded', {form: $(response.data), response:response, status:status});
		},
		complete: function (response, status) {
			This.emmit('complete', {response:response, status:status});
		}
	});
};

AjaxForm.prototype.submit = function (callback) {
	var This = this;
	This.__load(this.settings.url, this.settings.form_id, function (action, form, source) {
		if (action == 'success') {
			callback('load', source);
		}
	});
};


AjaxForm.prototype.on = function (action, callback) {
	if (typeof(this.action[action]) != undefined) {
		this.action[action].push(callback);
	}
	else {
		this.action.propotype.action = [callback];
	}
};

AjaxForm.prototype.emmit = function (action, data) {
	if (this.action.hasOwnProperty(action)) {
		while (this.action[action].length) {
			var callback = this.action[action].shift();
			calback(data);
		}
	}
};

The AjaxForm.on method can not work. can someguys point me the error ?