function doSave(value, type, name) {

    var blob;

    if (typeof window.Blob == "function") {

        blob = new Blob([value], {type: type});

    } else {

        var BlobBuilder = window.BlobBuilder || window.MozBlobBuilder || window.WebKitBlobBuilder || window.MSBlobBuilder;

        var bb = new BlobBuilder();

        bb.append(value);

        blob = bb.getBlob(type);

    }

    var URL = window.URL || window.webkitURL;

    var bloburl = URL.createObjectURL(blob);

    var anchor = document.createElement("a");

    if ('download' in anchor) {

        anchor.style.visibility = "hidden";

        anchor.href = bloburl;

        anchor.download = name;

        document.body.appendChild(anchor);

        var evt = document.createEvent("MouseEvents");

        evt.initEvent("click", true, true);

        anchor.dispatchEvent(evt);

        document.body.removeChild(anchor);

    } else if (navigator.msSaveBlob) {

        navigator.msSaveBlob(blob, name);

    } else {

        location.href = bloburl;

    }

}

var test = {

    a: [1, 2],

    b: [3, 4]

}

doSave(JSON.stringify(test), "text/latex", "hello.txt");