浏览器环境下js对文件进行写入

//写文件
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(test, "text/latex", "hello.txt");