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How do you set the name of a blob file in JavaScript when force downloading it through
window.location
?
function newFile(data) {
var json = JSON.stringify(data);
var blob = new Blob([json], {type: "octet/stream"});
var url = window.URL.createObjectURL(blob);
window.location.assign(url);
Running the above code downloads a file instantly without a page refresh that looks like:
bfefe410-8d9c-4883-86c5-d76c50a24a1d
I want to set the filename as my-download.json instead.
Create a hidden <a> tag.
Set its href attribute to the blob's URL.
Set its download attribute to the filename.
Click on the <a> tag.
Here is a simplified example (jsfiddle):
var saveData = (function () {
var a = document.createElement("a");
document.body.appendChild(a);
a.style = "display: none";
return function (data, fileName) {
var json = JSON.stringify(data),
blob = new Blob([json], {type: "octet/stream"}),
url = window.URL.createObjectURL(blob);
a.href = url;
a.download = fileName;
a.click();
window.URL.revokeObjectURL(url);
}());
var data = { x: 42, s: "hello, world", d: new Date() },
fileName = "my-download.json";
saveData(data, fileName);
I wrote this example just to illustrate the idea, in production code use FileSaver.js instead.
Notes
Older browsers don't support the "download" attribute, since it's part of HTML5.
Some file formats are considered insecure by the browser and the download fails. Saving JSON files with txt extension works for me.
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I just wanted to expand on the accepted answer with support for Internet Explorer (most modern versions, anyways), and to tidy up the code using jQuery:
$(document).ready(function() {
saveFile("Example.txt", "data:attachment/text", "Hello, world.");
function saveFile (name, type, data) {
if (data !== null && navigator.msSaveBlob)
return navigator.msSaveBlob(new Blob([data], { type: type }), name);
var a = $("<a style='display: none;'/>");
var url = window.URL.createObjectURL(new Blob([data], {type: type}));
a.attr("href", url);
a.attr("download", name);
$("body").append(a);
a[0].click();
window.URL.revokeObjectURL(url);
a.remove();
Here is an example Fiddle. Godspeed.
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Same principle as the solutions above. But I had issues with Firefox 52.0 (32 bit) where large files (>40 MBytes) are truncated at random positions. Re-scheduling the call of revokeObjectUrl() fixes this issue.
function saveFile(blob, filename) {
if (window.navigator.msSaveOrOpenBlob) {
window.navigator.msSaveOrOpenBlob(blob, filename);
} else {
const a = document.createElement('a');
document.body.appendChild(a);
const url = window.URL.createObjectURL(blob);
a.href = url;
a.download = filename;
a.click();
setTimeout(() => {
window.URL.revokeObjectURL(url);
document.body.removeChild(a);
}, 0)
jsfiddle example
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var json = JSON.stringify(data);
//IE11 support
if (window.navigator && window.navigator.msSaveOrOpenBlob) {
let blob = new Blob([json], {type: "application/json"});
window.navigator.msSaveOrOpenBlob(blob, fileName);
} else {// other browsers
let file = new File([json], fileName, {type: "application/json"});
let exportUrl = URL.createObjectURL(file);
window.location.assign(exportUrl);
URL.revokeObjectURL(exportUrl);
<button onclick="newFile({a:1}, 'file.json')">Export data to JSON</button>
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const a = document.createElement("a");
a.href = URL.createObjectURL(
new Blob([JSON.stringify(data, null, 2)], {
type: "application/json"
a.setAttribute("download", "data.json");
document.body.appendChild(a);
a.click();
document.body.removeChild(a);
<button onclick="export2json()">Export data to json file</button>
saveFileOnUserDevice = function(file){ // content: blob, name: string
if(navigator.msSaveBlob){ // For ie and Edge
return navigator.msSaveBlob(file.content, file.name);
else{
let link = document.createElement('a');
link.href = window.URL.createObjectURL(file.content);
link.download = file.name;
document.body.appendChild(link);
link.dispatchEvent(new MouseEvent('click', {bubbles: true, cancelable: true, view: window}));
link.remove();
window.URL.revokeObjectURL(link.href);
HTML:
<button onclick="downloadUrl('https://i.imgur.com/AD3MbBi.jpg', 'cat.jpg')">Download</button>
JavaScript:
function downloadUrl(url, filename) {
let xhr = new XMLHttpRequest();
xhr.open("GET", url, true);
xhr.responseType = "blob";
xhr.onload = function(e) {
if (this.status == 200) {
const blob = this.response;
const a = document.createElement("a");
document.body.appendChild(a);
const blobUrl = window.URL.createObjectURL(blob);
a.href = blobUrl;
a.download = filename;
a.click();
setTimeout(() => {
window.URL.revokeObjectURL(blobUrl);
document.body.removeChild(a);
}, 0);
xhr.send();
window.location.assign did not work for me. it downloads fine but downloads without an extension for a CSV file on Windows platform. The following worked for me.
var blob = new Blob([csvString], { type: 'text/csv' });
//window.location.assign(window.URL.createObjectURL(blob));
var link = window.document.createElement('a');
link.href = window.URL.createObjectURL(blob);
// Construct filename dynamically and set to link.download
link.download = link.href.split('/').pop() + '.' + extension;
document.body.appendChild(link);
link.click();
document.body.removeChild(link);
this is a good easy solution for it.
function downloadBloob(blob,FileName) {
var link = document.createElement("a"); // Or maybe get it from the current document
link.href = blob;
link.download = FileName;
link.click();
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