Parsing and working with url parameters

url-params-function.js

// Function for parsing params from url (returning params in javascript object)
var parseUrlParams = function () {
	var parReg = /[\?\&][a-zA-z0-9-~]+/g,
		params = window.location.search.match(parReg),
		result = {};

	for (var i = params.length - 1; i >= 0; i--) {
		params[i] = params[i].substring(1);
		var valReg = new RegExp('[?&]'+params[i]+'=([^&#]*)'),
			val = window.location.search.match(valReg) ? window.location.search.match(valReg)[1] : null;
		result[params[i].replace('~', '_')] = val === 'true' ? true : val;
	}
	return result;
};

url-params-singleton.js

// Singleton creating object with property "params" and method getParam(paramName)
/*
 * Usage:
 * var urlParams = new UrlParams();
 * urlParams.params 				// returning object with all url parameters
 * urlParams.getParam(name) 		// method returning param value or false (if param doesn't exits)
*/
var UrlParams;
(function (){
	var instance;
	UrlParams = function UrlParams(){
		if (instance) {
			return instance;
		}
		instance = this;

		this.params = {};
		
		var parReg = /[\?\&][a-zA-z0-9-~]+/g,
		params = window.location.search.match(parReg);

		for (var i = params.length - 1; i >= 0; i--) {
			params[i] = params[i].substring(1);
			var valReg = new RegExp('[?&]'+params[i]+'=([^&#]*)'),
				val = window.location.search.match(valReg) ? window.location.search.match(valReg)[1] : null;
			this.params[params[i].replace('~', '_')] = val === 'true' ? true : val;
		}
	};
}());

UrlParams.prototype.getParam = function(param) {
	return this.params[param] !== undefined ? this.params[param] : false;
};