(function() {
    if (!window.translate) {
        /** 
        * this global function is for string substitution
        * @property {string} string to translate.
        * @property {string} as much 
        * return STRING
        */
        window.translate = function() {
            var html = [];
            var arguments = arguments;
            var string = arguments[0];

            var objIndex = 0;
            var reg = /%s/;
            var parts = [];

            /** 
            * analyze the string, extract the parts with the %s identifier.
            */
            for (var m = reg.exec(string); m; m = reg.exec(string)) {
                // m[0][0] gives undefined in IE
                parts.push(string.substr(0, m[0][0] === "%" ? m.index : m.index));
                parts.push("%s");
                string = string.substr(m.index + m[0].length);
            }
            parts.push(string);

            /** 
            * analyze the parts, replace the %s with the given arguments. 
            * beware of undefined!
            */
            for (var i = 0; i < parts.length; ++i) {
                var part = parts[i];
                if (part && part == "%s") {
                    var object = arguments[++objIndex];
                    if (object == undefined) {
                        html.push("%s");
                    } else {
                        html.push(object);
                    };
                } else {
                    html.push(part);
                }
            }

            /** 
            * Join the array and return as string.
            */
            return html.join('');
        }
    };
})();