window.getUrlParameter = function getUrlParameter(paramName) {
    var pageUrl = decodeURIComponent(window.location.search.substring(1)),
        urlVariables = pageUrl.split('&'),
        urlParamName;

    for (var i = 0; i < urlVariables.length; i++) {
        urlParamName = urlVariables[i].split('=');

        if (urlParamName[0] === paramName) {
            return urlParamName[1] === undefined ? true : urlParamName[1];
        }
    }
};