AWS Signed Cookie from Signed URL cross domain

## aws-signed-cookie-from-signed-url.js
/**
 * aws-signed-cookie-from-signed-url.js
 * Include this file in the landing page of the CloudFront assets where a signed url (from another domain) would direct users to
 * If the url is signed (i.e. has Policy, Signature and Key-Pair-Id params) it will create cookies for those attributes based on AWS rules
 * This will allow the internal navigation of CloudFront assets without the need of signed urls for each asset
 */

/**
 *
 */
function getUrlVars() {
	var vars = {};
	var parts = window.location.href.replace(/[?&]+([^=&]+)=([^&]*)/gi, function(m,key,value) {
		vars[key] = value;
	});
	return vars;
}

/**
 *
 * @param parameter
 * @param defaultvalue
 * @returns {*}
 */
function getUrlParam(parameter, defaultvalue){
	var urlparameter = defaultvalue;
	if(window.location.href.indexOf(parameter) > -1){
		urlparameter = getUrlVars()[parameter];
	}
	return urlparameter;
}

/**
 *
 * @param cname
 * @param cvalue
 * @param exdays
 */
function setCookie(cname, cvalue, exdays) {
	var d = new Date();
	d.setTime(d.getTime() + (exdays*24*60*60*1000));
	var expires = "expires="+ d.toUTCString();
	document.cookie = cname + "=" + cvalue + ";" + expires + ";path=/";
}

var Policy = getUrlParam('Policy', '');
var Signature = getUrlParam('Signature', '');
var KeyPairId = getUrlParam('Key-Pair-Id', '');

if (Policy != '' && Signature != '' && KeyPairId != '') {
	//delete cookie first
	setCookie('CloudFront-Policy', '', 0);
	setCookie('CloudFront-Signature', '', 0);
	setCookie('CloudFront-Key-Pair-Id', '', 0);

	//set the cookie
	setCookie('CloudFront-Policy', Policy, 1);
	setCookie('CloudFront-Signature', Signature, 1);
	setCookie('CloudFront-Key-Pair-Id', KeyPairId, 1);
}