(function(window) {

	var document = window.document,
		initFormCookies = function(form) {
			addQueryParamsToCookies();
			addCookieInputsToForm(form);
		},
		addQueryParamsToCookies = function() {
			var params = parseQueryString(document.location.search.substring(1)),
				keys = ['utm_source', 'utm_medium', 'utm_campaign', 'ref'],
				cookies = ['domain=.'+window.location.hostname.split('.').slice(-2).join('.')],
				cookieString = '';

			for (var i = 0; i < keys.length; i++) {
				if (params[keys[i]]) {
					cookies.push([keys[i], params[keys[i]]].join('='));
				}
			}
			cookieString = cookies.join('; ')
			document.cookie = cookieString
		},
		addCookieInputsToForm = function(form) {
			var cookies = parseQueryString(document.cookie, '; '),
				keys = ['utm_source', 'utm_medium', 'utm_campaign', 'ref'];

			for (var i = 0; i < keys.length; i++) {
				if (!cookies[keys[i]]) continue;
				var input = document.createElement('input');
				input.type = 'hidden';
				input.name = keys[i];
				input.value = cookies[keys[i]];
				form.appendChild(input);
			}
		},
		parseQueryString = function(queryString, delimiter = '&', separator = '=') {
			var pairs = queryString.split(delimiter),
				pair = [],
				params = {};

			pairs.map(function(item) {
				pair = item.split(separator);
				if (pair.length < 2) { return false; }
				params[pair[0]] = pair[1];
			});

			return params;
		};

	window.addEventListener('DOMContentLoaded', function() {
		var forms = document.querySelectorAll('.email-capture-form');
		for (i = 0; i < forms.length; i++) {
			initFormCookies(forms[i]);
		}
	});

}(window));