用javascript获取querystring参数

//获取QueryString的数组
        function getQueryString() {
            var result = location.search.match(new RegExp("[\?\&][^\?\&]+=[^\?\&]+", "g"));
            if (result == null) {
                return "";
            }
            for (var i = 0; i < result.length; i++) {
                result[i] = result[i].substring(1);
            }
            return result;
        }

        //根据QueryString参数名称获取值
        function getQueryStringByName(name) {
            var result = location.search.match(new RegExp("[\?\&]" + name + "=([^\&]+)", "i"));
            if (result == null || result.length < 1) {
                return "";
            }
            return result[1];
        }

        //根据QueryString参数索引获取值
        function getQueryStringByIndex(index) {
            if (index == null) {
                return "";
            }
            var queryStringList = getQueryString();
            if (index >= queryStringList.length) {
                return "";
            }
            var result = queryStringList[index];
            var startIndex = result.indexOf("=") + 1;
            result = result.substring(startIndex);
            return result;
        }