[Rasy]

someQuestions, как вариант

var saveData = (function () {
        var a = document.createElement("a");
        document.body.appendChild(a);
        a.style = "display: none";
        return function (data, fileName) {
           var blob = new Blob([data], {type: "octet/stream"}),
               url = window.URL.createObjectURL(blob);
            a.href = url;
            a.download = fileName;
            a.click();
            window.URL.revokeObjectURL(url);
        };
    }());
    saveData('test', 'example2.txt');