1165

Is there a way to create a text file on the client side and prompt the user to download it without any interaction with the server?

I know I can't write directly to their machine (security and all), but can I create the file and prompt them to save it?

1

23 Answers 23

1070

Simple solution for HTML5 ready browsers...

function download(filename, text) { var element = document.createElement('a'); element.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(text)); element.setAttribute('download', filename); element.style.display = 'none'; document.body.appendChild(element); element.click(); document.body.removeChild(element); }
form * { display: block; margin: 10px; }
<form onsubmit="download(this['name'].value, this['text'].value)"> <input type="text" name="name" value="test.txt"> <textarea name="text"></textarea> <input type="submit" value="Download"> </form>

Usage

download('test.txt', 'Hello world!'); 
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24 Comments

Yep. This is exactly what @MatthewFlaschen has posted here about 3 years ago.
Yes, but with download attribute you can specify file name ;-)
Chrome only appends the txt extension if you do not provide an extension in the filename. If you do download("data.json", data) it'll work as expected.
This worked for me in Chrome (73.0.3683.86), and Firefox (66.0.2). It did NOT work in IE11 (11.379.17763.0) and Edge (44.17763.1.0).
There's no need to attach the element to the DOM.
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490

You can use data URIs. Browser support varies; see Wikipedia. Example:

<a href="data:application/octet-stream;charset=utf-16le;base64,//5mAG8AbwAgAGIAYQByAAoA">text file</a> 

The octet-stream is to force a download prompt. Otherwise, it will probably open in the browser.

For CSV, you can use:

<a href="data:application/octet-stream,field1%2Cfield2%0Afoo%2Cbar%0Agoo%2Cgai%0A">CSV Octet</a> 

Try the jsFiddle demo.

26 Comments

This is not a cross browser solution but definitely something worth looking at. For example IE limits support to data uri. IE 8 limits size to 32KB and IE 7 and lower doesn't support at all.
in Chrome Version 19.0.1084.46, this method generates the following warning : "Resource interpreted as Document but transferred with MIME type text/csv: "data:text/csv,field1%2Cfield2%0Afoo%2Cbar%0Agoo%2Cgai%0A"." A download is not triggered
It does work in Chrome now (tested against v20 and v21) but not IE9 (that might just be the jsFiddle, but somehow I doubt it).
The correct charset is almost certainly UTF-16, unless you have code converting it to UTF-8. JavaScript uses UTF-16 internally. If you have a text or CSV file, start the string with '\ufeff', the Byte Order Mark for UTF-16BE, and text editors will be able to read non-ASCII characters correctly.
Just add download="txt.csv" attribute in order to have proper file name and extension and to tell your OS what to do with it.
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339

An example for IE 10+, Firefox and Chrome (and without jQuery or any other library):

function save(filename, data) { const blob = new Blob([data], {type: 'text/csv'}); if(window.navigator.msSaveOrOpenBlob) { window.navigator.msSaveBlob(blob, filename); } else{ const elem = window.document.createElement('a'); elem.href = window.URL.createObjectURL(blob); elem.download = filename; document.body.appendChild(elem); elem.click(); document.body.removeChild(elem); } } 

Note that, depending on your situation, you may also want to call URL.revokeObjectURL after removing elem. According to the docs for URL.createObjectURL:

Each time you call createObjectURL(), a new object URL is created, even if you've already created one for the same object. Each of these must be released by calling URL.revokeObjectURL() when you no longer need them. Browsers will release these automatically when the document is unloaded; however, for optimal performance and memory usage, if there are safe times when you can explicitly unload them, you should do so.

14 Comments

For AngularJS 1.x apps, you can build an array of Urls as they are created and then clean them up in the $onDestroy function of the component. This is working great for me.
Other answers led to Failed: network error in Chrome. This one works well.
This worked for me in Chrome (73.0.3683.86), Firefox (66.0.2), IE11 (11.379.17763.0) and Edge (44.17763.1.0).
For those looking to avoid garbage collection on the URL or strange behavior, just declare your blob like this: const url = URL.createObjectURL(blob, { oneTimeOnly: true }). You can always save the blob and generate a new Url later if needed.
Consider adding elem.style.display = 'none'; before document.body.appendChild(elem); if you want to avoid any potential for visual glitches
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206

All of the above example works just fine in chrome and IE, but fail in Firefox. Please do consider appending an anchor to the body and removing it after click.

var a = window.document.createElement('a'); a.href = window.URL.createObjectURL(new Blob(['Test,Text'], {type: 'text/csv'})); a.download = 'test.csv'; // Append anchor to body. document.body.appendChild(a); a.click(); // Remove anchor from body document.body.removeChild(a); 

4 Comments

However: there's an open bug in IE 10 (and I've still seen it in 11) that throws "Access is denied" on the a.click() line because it thinks the blob URL is cross-origin.
@Matt data uri is cross origin in some browsers. as far as I know, not just in msie, but in chrome as well. you can test it by trying to inject javascript with data uri. It won't be able to access other parts of the site...
"All of the above example works just fine in chrome and IE, but fail in Firefox.". Since the order of answers can change over time, it's unclear which answers were above yours when you wrote this. Can you indicate exactly which approaches don't work in Firefox?
👍 This blob approach works much better for very large files.
136

I'm happily using FileSaver.js. Its compatibility is pretty good (IE10+ and everything else), and it's very simple to use:

var blob = new Blob(["some text"], { type: "text/plain;charset=utf-8;", }); saveAs(blob, "thing.txt"); 

9 Comments

This works great on Chrome. How do I allow the user to specific the location of the file on disk?
Wow, thanks for the easy to use library. This is easily the best answer, and who cares about people using HTML < 5 these days any ways?
@gregm I'm not sure you can with this plugin.
@gregm: You mean the download location? That's not related to FileSaver.js, you need to set your browser configuration so that it asks for a folder before every download, or use the rather new download attribute on <a>.
This is a GREAT solution for IE 10+ family of browsers. IE doesn't support the download HTML 5 tag yet and the other solutions on this page (and other SO pages discussing the same problem) were simply not working for me. FileSaver ftw!
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67

Use Blob:

function download(content, mimeType, filename){ const a = document.createElement('a') // Create "a" element const blob = new Blob([content], {type: mimeType}) // Create a blob (file-like object) const url = URL.createObjectURL(blob) // Create an object URL from blob a.setAttribute('href', url) // Set "a" element link a.setAttribute('download', filename) // Set download filename a.click() // Start downloading } 

Blob is being supported by all modern browsers.
Caniuse support table for Blob:

Here is a Fiddle

And here MDN Docs

The Blob object represents a blob, which is a file-like object of immutable, raw data; they can be read as text or binary data...

5 Comments

This is a copy of the existing answer here: stackoverflow.com/a/33542499/1250319
@Daniel This is not a copy, there's subtle but important difference between the two answers.
How so @xuhdev? This answer contains the exact same elements as the other answer but without the additional window.navigator.msSaveOrOpenBlob alternative. That doesn't make this a new answer. The other answer uses Blob + using URL.createObjectURL + a dynamically created <a> tag whose click is immediately called.
@Daniel This answer does not modify document as the other one does. The other answer doesn't explain why modifying the DOM is needed and what side effect it may have. So I think there are some positive points on this answer (hence "important difference between the two answers"). Of course, the other answer has its own positive sides, as you pointed out.
Thanks for the clarification @xuhdev, fair enough 👍 I've retracted my flag but maintain the downvote because I think the difference about the DOM could have been a comment or edit to the other answer I mentioned.
22

The following method works in IE11+, Firefox 25+ and Chrome 30+:

<a id="export" class="myButton" download="" href="#">export</a> <script> function createDownloadLink(anchorSelector, str, fileName){ if(window.navigator.msSaveOrOpenBlob) { var fileData = [str]; blobObject = new Blob(fileData); $(anchorSelector).click(function(){ window.navigator.msSaveOrOpenBlob(blobObject, fileName); }); } else { var url = "data:text/plain;charset=utf-8," + encodeURIComponent(str); $(anchorSelector).attr("download", fileName); $(anchorSelector).attr("href", url); } } $(function () { var str = "hi,file"; createDownloadLink("#export",str,"file.txt"); }); </script> 

See this in Action: http://jsfiddle.net/Kg7eA/

Firefox and Chrome support data URI for navigation, which allows us to create files by navigating to a data URI, while IE doesn't support it for security purposes.

On the other hand, IE has API for saving a blob, which can be used to create and download files.

3 Comments

I just used jquery to attach events(onclick and onready) and set attributes, which you can also do with vanilla JS. The core part(window.navigator.msSaveOrOpenBlob) doesn't need jquery.
There is still the limitation of size for the data uri approach, isn't it?
msSaveOrOpenBlob is shown as obsolete here: developer.mozilla.org/en-US/docs/Web/API/Navigator/msSaveBlob
22

We can use the URL api, in particular URL.createObjectURL(), and the Blob api to encode and download pretty much anything.

If your download is small, this works fine:

document.body.innerHTML += `<a id="download" download="PATTERN.json" href="${URL.createObjectURL(new Blob([JSON.stringify("HELLO WORLD", null, 2)]))}"> Click me</a>` download.click() download.outerHTML = ""


If your download is huge, instead of using the DOM, a better way is to create a link element with the download parameters, and trigger a click.

Notice the link element isn't appended to the document but the click work anyway! This is possible to create a download of many hundreds of Mo this way, as the DOM is not modified (Otherwise the huge URL in the DOM can be a source of tab freeze).

const stack = { some: "stuffs", alot: "of them!" } BUTTONDOWNLOAD.onclick = (function(){ let j = document.createElement("a") j.download = "stack_"+Date.now()+".json" j.href = URL.createObjectURL(new Blob([JSON.stringify(stack, null, 2)])) j.click() })
<button id="BUTTONDOWNLOAD">DOWNLOAD!</button>


Bonus! Download any cyclic objects, avoid the errors:

TypeError: cyclic object value (Firefox) TypeError: Converting

circular structure to JSON (Chrome and Opera) TypeError: Circular

reference in value argument not supported (Edge)

Using https://github.com/douglascrockford/JSON-js/blob/master/cycle.js

On this example, downloading the document object as json.

/* JSON.decycle */ if(typeof JSON.decycle!=="function"){JSON.decycle=function decycle(object,replacer){"use strict";var objects=new WeakMap();return(function derez(value,path){var old_path;var nu;if(replacer!==undefined){value=replacer(value)} if(typeof value==="object"&&value!==null&&!(value instanceof Boolean)&&!(value instanceof Date)&&!(value instanceof Number)&&!(value instanceof RegExp)&&!(value instanceof String)){old_path=objects.get(value);if(old_path!==undefined){return{$ref:old_path}} objects.set(value,path);if(Array.isArray(value)){nu=[];value.forEach(function(element,i){nu[i]=derez(element,path+"["+i+"]")})}else{nu={};Object.keys(value).forEach(function(name){nu[name]=derez(value[name],path+"["+JSON.stringify(name)+"]")})} return nu} return value}(object,"$"))}} document.body.innerHTML += `<a id="download" download="PATTERN.json" href="${URL.createObjectURL(new Blob([JSON.stringify(JSON.decycle(document), null, 2)]))}"></a>` download.click()

Comments

18

The package js-file-download from github.com/kennethjiang/js-file-download handles edge cases for browser support:

View source to see how it uses techniques mentioned on this page.

Installation

yarn add js-file-download npm install --save js-file-download 

Usage

import fileDownload from 'js-file-download' // fileDownload(data, filename, mime) // mime is optional fileDownload(data, 'filename.csv', 'text/csv') 

1 Comment

Thanks - just tested - works with Firefox, Chrome and Edge on Windows
16

This solution is extracted directly from tiddlywiki's (tiddlywiki.com) github repository. I have used tiddlywiki in almost all browsers and it works like a charm:

function(filename,text){ // Set up the link var link = document.createElement("a"); link.setAttribute("target","_blank"); if(Blob !== undefined) { var blob = new Blob([text], {type: "text/plain"}); link.setAttribute("href", URL.createObjectURL(blob)); } else { link.setAttribute("href","data:text/plain," + encodeURIComponent(text)); } link.setAttribute("download",filename); document.body.appendChild(link); link.click(); document.body.removeChild(link); } 

Github repo: Download saver module

2 Comments

It works very nicely on Chrome, but not on Firefox. It does make a file and downloads it, but the file is empty. No content. Any ideas why? Haven't tested on IE...
except that the function has no name, this is my favourite
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function download(filename, text) { var element = document.createElement('a'); element.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(text)); element.setAttribute('download', filename); element.style.display = 'none'; document.body.appendChild(element); element.click(); document.body.removeChild(element); } // Start file download. download("hello.txt","This is the content of my file :)"); 

Original article : https://ourcodeworld.com/articles/read/189/how-to-create-a-file-and-generate-a-download-with-javascript-in-the-browser-without-a-server

Comments

11

Solution that work on IE10: (I needed a csv file, but it's enough to change type and filename to txt)

var csvContent=data; //here we load our csv data var blob = new Blob([csvContent],{ type: "text/csv;charset=utf-8;" }); navigator.msSaveBlob(blob, "filename.csv") 

1 Comment

Ludovic's answer includes this big, plus support for the other browsers.
11

If you just want to convert a string to be available for download you can try this using jQuery.

$('a.download').attr('href', 'data:application/csv;charset=utf-8,' + encodeURI(data)); 

1 Comment

Scape data with encodeURI might be needed as I suggested here before being able to comment: stackoverflow.com/a/32441536/4928558
9

As mentioned before, filesaver is a great package to work with files on the client side. But, it is not do well with large files. StreamSaver.js is an alternative solution (which is pointed in FileServer.js) that can handle large files:

const fileStream = streamSaver.createWriteStream('filename.txt', size); const writer = fileStream.getWriter(); for(var i = 0; i < 100; i++){ var uint8array = new TextEncoder("utf-8").encode("Plain Text"); writer.write(uint8array); } writer.close() 

1 Comment

Text Encoder is highly experimental right now, I'd suggest avoiding (or polyfilling) it.
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var element = document.createElement('a'); element.setAttribute('href', 'data:text/text;charset=utf-8,' + encodeURI(data)); element.setAttribute('download', "fileName.txt"); element.click(); 

1 Comment

What are the differences between this approach and creating a Blob?
7

Based on @Rick answer which was really helpful.

You have to scape the string data if you want to share it this way:

$('a.download').attr('href', 'data:application/csv;charset=utf-8,'+ encodeURI(data)); 

` Sorry I can not comment on @Rick's answer due to my current low reputation in StackOverflow.

An edit suggestion was shared and rejected.

1 Comment

I was not able to accept the suggestion. Strange... I updated the code.
3

This below function worked.

 private createDownloadableCsvFile(fileName, content) { let link = document.createElement("a"); link.download = fileName; link.href = `data:application/octet-stream,${content}`; return link; } 

1 Comment

can you open the file in a new tab keeping the fileName assigned, but not downloading, just opening in a tab?
2

Download file with extensions or without extensions in the example, I am using JSON. You may add your data and extensions. You may use 'MAC-Addresses.json' here, as per your wish. If you want to add an extension, add there, else, just write the file name without extensions.

let myJson = JSON.stringify(yourdata); let element = document.createElement('a'); element.setAttribute('href', 'data:text/plain;charset=utf-8,' + encodeURIComponent(myJson)); element.setAttribute('download', 'MAC-Addresses.json'); element.style.display = 'none'; document.body.appendChild(element); element.click(); document.body.removeChild(element); 

1 Comment

Nice code snippet, was useful for me.
1

For me this worked perfectly, with the same filename and extension getting downloaded

<a href={"data:application/octet-stream;charset=utf-16le;base64," + file64 } download={title} >{title}</a>

'title' is the file name with extension i.e, sample.pdf, waterfall.jpg, etc..

'file64' is the base64 content something like this i.e, Ww6IDEwNDAsIFNsaWRpbmdTY2FsZUdyb3VwOiAiR3JvdXAgQiIsIE1lZGljYWxWaXNpdEZsYXRGZWU6IDM1LCBEZW50YWxQYXltZW50UGVyY2VudGFnZTogMjUsIFByb2NlZHVyZVBlcmNlbnQ6IDcwLKCFfSB7IkdyYW5kVG90YWwiOjEwNDAsIlNsaWRpbmdTY2FsZUdyb3VwIjoiR3JvdXAgQiIsIk1lZGljYWxWaXNpdEZsYXRGZWUiOjM1LCJEZW50YWxQYXltZW50UGVyY2VudGFnZSI6MjUsIlByb2NlZHVyZVBlcmNlbnQiOjcwLCJDcmVhdGVkX0J5IjoiVGVycnkgTGVlIiwiUGF0aWVudExpc3QiOlt7IlBhdGllbnRO

Comments

1

I would use an <a></a> tag then set the href='path'. Afterwards, place an image in between the <a> elements so that I can have a visual to see it. If you wanted to, you could create a function that will change the href so that it won't just be the same link but be dynamic.

Give the <a> tag an id as well if you want to access it with javascript.

Starting with the HTML Version:

<a href="mp3/tupac_shakur-how-do-you-want-it.mp3" download id="mp3Anchor"> <img src="some image that you want" alt="some description" width="100px" height="100px" /> </a> 

Now with JavaScript:

*Create a small json file*; const array = [ "mp3/tupac_shakur-how-do-you-want-it.mp3", "mp3/spice_one-born-to-die.mp3", "mp3/captain_planet_theme_song.mp3", "mp3/tenchu-intro.mp3", "mp3/resident_evil_nemesis-intro-theme.mp3" ]; //load this function on window window.addEventListener("load", downloadList); //now create a function that will change the content of the href with every click function downloadList() { var changeHref=document.getElementById("mp3Anchor"); var j = -1; changeHref.addEventListener("click", ()=> { if(j < array.length-1) { j +=1; changeHref.href=""+array[j]; } else { alert("No more content to download"); } } 

Comments

1

The following method works in IE10+, Edge, Opera, FF and Chrome:

const saveDownloadedData = (fileName, data) => { if(~navigator.userAgent.indexOf('MSIE') || ~navigator.appVersion.indexOf('Trident/')) { /* IE9-11 */ const blob = new Blob([data], { type: 'text/csv;charset=utf-8;' }); navigator.msSaveBlob(blob, fileName); } else { const link = document.createElement('a') link.setAttribute('target', '_blank'); if(Blob !== undefined) { const blob = new Blob([data], { type: 'text/plain' }); link.setAttribute('href', URL.createObjectURL(blob)); } else { link.setAttribute('href', 'data:text/plain,' + encodeURIComponent(data)); } ~window.navigator.userAgent.indexOf('Edge') && (fileName = fileName.replace(/[&\/\\#,+$~%.'':*?<>{}]/g, '_')); /* Edge */ link.setAttribute('download', fileName); document.body.appendChild(link); link.click(); document.body.removeChild(link); } } 

So, just call the function:

saveDownloadedData('test.txt', 'Lorem ipsum'); 

Comments

0

I may be the strange one here, but why is nobody talking about the window.open() function?

const blob = new Blob([data], {type: 'text/csv'}); const dataUrl = URL.createObjectURL(blob); window.open(dataUrl); 

Isn't it like billions times less hacky than to create a fake DOM link and trigger a fake user click event?

This solution may possibly have some downsides of browser popup blocking if function is called in an async context, but let's discuss that so that future readers had at least some alternatives to hacks or had at least some explanation why those hacks are the only way.

One more way that's probably 100% browser popup blocking-proof:

window.location.href = dataUrl; 

1 Comment

This approach does not set the file name or triggers a download. The download attribute on the anchor tag is intended exactly for this purpose. A "fake" anchor is not required. The user may click the link to download.
-28

If the file contains text data, a technique I use is to put the text into a textarea element and have the user select it (click in textarea then ctrl-A) then copy followed by a paste to a text editor.

1 Comment

I had considered that, but from a user-friendliness point, this is disastrous. Also, the file has to be saved with a CSV extension. Try telling that to your users.

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