Load the current querystring parameters into an associative array, taking into account repeated keys

gistfile1.js

// By JonathanConway.net
// Based off original code by Andy E. http://stackoverflow.com/questions/901115/get-querystring-values-with-jquery/2880929#2880929

Object.prototype.isArray = function () {
	/// <summary>
	///  Returns true if this object is an array.
	/// </summary>
	return !(this.push === undefined);
};

var urlParams = {};
(function () {
	var e,
		a = /\+/g,  // Regex for replacing addition symbol with a space
		r = /([^&=]+)=?([^&]*)/g,
		d = function (s) { return decodeURIComponent(s.replace(a, " ")); },
		q = window.location.search.substring(1),
		key,
		value;

	while (e = r.exec(q)) {
		key = d(e[1]);
		value = d(e[2]);
		
		if (urlParams[key].isArray !== undefined && typeof urlParams[key] === 'undefined')
			urlParams[key] = value;
		else
			if (urlParams[key].isArray())
				urlParams[key].push(value);
			else
				urlParams[key] = [urlParams[key], value];
	}
})();