Simple AJAX call helper, with lock mechanism to prevent duplicated concurrent connections. It sends data in JSON format, you can easily adapt it to to your need. Dependencies: jQuery ($.ajax) and UnderscoreJS. You can easily remove UnderscoreJS code.

API Helper

/**
 * Simple AJAX call helper, with lock mechanism to prevent duplicated concurrent connections.
 * It sends data in JSON format, you can easily adapt it to to your need.
 * Dependencies: jQuery ($.ajax) and UnderscoreJS. You can easily remove UnderscoreJS code.
 */
var API = new function() {
	var self = this;

	// Lock to prevent duplicated concurrent API calls.
	self.locks = {};

	/**
	 * @param string uri E.g. login
	 * @return string API URL
	 */
	self.endpoint = function(uri) {
		return  'http://example.com' + uri;
	};

	/**
	 * Simple lock mechanism to prevent concurrent duplicated calls.
	 * @param string name Unique name for AJAX call. E.g. "login"
	 * @return bool If true, proceed to perform AJAX call.
	 */
	self.accquireAJAX = function(name) {
		if (!_.has(self.locks, name))
			self.locks[name] = 0;

		// Release lock after 3 minutes
		var now = new Date().getTime(); // Timestamp in milliseconds
		if (now - self.locks[name] > 180000) {
			self.locks[name] = now;
			return true;
		}

		return false;
	};

	/**
	 * Simple lock mechanism to prevent concurrent duplicated calls.
	 * @param {string} name Unique name for AJAX call. E.g. "login"
	 */
	self.releaseAJAX = function(name) {
		self.locks[name] = 0;
	};

	/**
	 * Log AJAX response.
	 * @param {objext} context AJAX context
	 */
	self.ajaxLogger = function(context) {
		console.log(context);
	};

	/**
	 * Perform API call.
	 * @param {string} uri
	 * @param {JSON} options Key-value pair parameters
	 * @param {callback} success Optional.
	 * @param {callback} error Optional.
	 */
	self.call = function(uri, options, success, error) {
		if (!self.accquireAJAX(uri))
			return;

		console.log('Calling ' + uri);

		success = _.isUndefined(success) ? self.ajaxLogger : success;
		error = _.isUndefined(error) ? self.ajaxLogger : error;
		var data = JSON.stringify(options);

		$.ajax({
			url: self.endpoint(uri),
			type: 'POST',
			contentType: 'application/json',
			data: data,
			success: success,
			error: error,
			complete: function() {
				self.releaseAJAX(uri);
				console.log('Completed ' + uri);
			}
		});
	};
}; // API