Modify Querystring

addOrUpdateUrlParam: function(uri, paramKey, paramVal) {
    var regex = new RegExp("([?&])" + paramKey + "=[^&#]*", "i");
    if (regex.test(uri)) {
        uri = uri.replace(regex, '$1' + paramKey + "=" + paramVal);
    } else {
        var separator = /\?/.test(uri) ? "&" : "?";
        uri = uri + separator + paramKey + "=" + paramVal;
    }

    if (history.pushState) {
        var querystring = uri;
        history.pushState(null, null, querystring);
    }
}