JavaScript - How to download image from fetched in network [duplicate] - javascript

This is crazy but I don't know how to do this, and because of how common the words are, it's hard to find what I need on search engines. I'm thinking this should be an easy one to answer.
I want a simple file download, that would do the same as this:
Download!
But I want to use an HTML button, e.g. either of these:
<input type="button" value="Download!">
<button>Download!</button>
Likewise, is it possible to trigger a simple download via JavaScript?
$("#fileRequest").click(function(){ /* code to download? */ });
I'm definitely not looking for a way to create an anchor that looks like a button, use any back-end scripts, or mess with server headers or mime types.

You can trigger a download with the HTML5 download attribute.
Download
Where:
path_to_file is a path that resolves to an URL on the same origin. That means the page and the file must share the same domain, subdomain, protocol (HTTP vs. HTTPS), and port (if specified). Exceptions are blob: and data: (which always work), and file: (which never works).
proposed_file_name is the filename to save to. If it is blank, the browser defaults to the file's name.
Documentation: MDN, HTML Standard on downloading, HTML Standard on download, CanIUse

For the button you can do
<form method="get" action="file.doc">
<button type="submit">Download!</button>
</form>

HTML:
<button type="submit" onclick="window.open('file.doc')">Download!</button>

A simple JS solution:
function download(url) {
const a = document.createElement('a')
a.href = url
a.download = url.split('/').pop()
document.body.appendChild(a)
a.click()
document.body.removeChild(a)
}

With jQuery:
$("#fileRequest").click(function() {
// hope the server sets Content-Disposition: attachment!
window.location = 'file.doc';
});

You can do it with "trick" with invisible iframe. When you set "src" to it, browser reacts as if you would click a link with the same "href". As opposite to solution with form, it enables you to embed additional logic, for example activating download after timeout, when some conditions are met etc.
It is also very silient, there's no blinking new window/tab like when using window.open.
HTML:
<iframe id="invisible" style="display:none;"></iframe>
Javascript:
function download() {
var iframe = document.getElementById('invisible');
iframe.src = "file.doc";
}

Bootstrap Version
<a class="btn btn-danger" role="button" href="path_to_file"
download="proposed_file_name">
Download
</a>
Documented in Bootstrap 4 docs, and works in Bootstrap 3 as well.

I think this is the solution you were looking for
<button type="submit" onclick="window.location.href='file.doc'">Download!</button>
I hade a case where my Javascript generated a CSV file. Since there is no remote URL to download it I use the following implementation.
downloadCSV: function(data){
var MIME_TYPE = "text/csv";
var blob = new Blob([data], {type: MIME_TYPE});
window.location.href = window.URL.createObjectURL(blob);
}

You can hide the download link and make the button click it.
<button onclick="document.getElementById('link').click()">Download!</button>
<a id="link" href="file.doc" download hidden></a>

What about:
<input type="button" value="Download Now!" onclick="window.location = 'file.doc';">

In my testing the following works for all file types and browsers as long as you use a relative link:
<button>Download 2</button>
/assets/hello.txt is just a relative path on my site. Change it to your own relative path.
my_file.txt is the name you want the file to be called when it is downloaded.
Explanation
I noticed there were comments under a lot of the answers that said the browser would just try to open the file itself rather than downloading it depending on the file type. I discovered this to be true.
I made two buttons to test it out using two different methods:
<button onclick="window.location.href='/assets/hello.txt';">Download 1</button>
<button>Download 2</button>
Notes:
Button 1 opened the text file in a new browser tab. However, Button 1 would download the file for file types that it couldn't open itself (for example, .apk files).
Button 2 downloaded the text file. However, Button 2 only downloaded the file if the path was relative. When I changed the path to an absolute path, then the browser opened it in a new tab.
I tested this on Firefox, Safari, and Chrome.

Hello I just include the word 'download' and works well.
<a href="file.pdf" download>Download</a>
So in javascript you can use the follow:
function onStartedDownload(id) {
console.log(`Started downloading: ${id}`);
}
function onFailed(error) {
console.log(`Download failed: ${error}`);
}
var downloadUrl = "https://example.org/image.png";
var downloading = browser.downloads.download({
url : downloadUrl,
filename : 'my-image-again.png',
conflictAction : 'uniquify'
});
downloading.then(onStartedDownload, onFailed);

If your looking for a vanilla JavaScript (no jQuery) solution and without using the HTML5 attribute you could try this.
const download = document.getElementById("fileRequest");
download.addEventListener('click', request);
function request() {
window.location = 'document.docx';
}
.dwnld-cta {
border-radius: 15px 15px;
width: 100px;
line-height: 22px
}
<h1>Download File</h1>
<button id="fileRequest" class="dwnld-cta">Download</button>

<button>Download!</button>
This will download the file as .doc file extension is not supported to be opened in browser.
One of the simplest way for button and the text-decoration will help to alter or to remove the text decoration of the link.

Anywhere between your <body> and </body> tags, put in a button using the below code:
<button>
<a href="file.doc" download>Click to Download!</a>
</button>
This is sure to work!

all you need to do is add Download after the file name which you have entered:
Before:
Download!
After
<a href="file.doc" Download >Download!</a>
Make sure the download is written with a capital letter otherwise it's not gonna work.

This is what finally worked for me since the file to be downloaded was determined when the page is loaded.
JS to update the form's action attribute:
function setFormAction() {
document.getElementById("myDownloadButtonForm").action = //some code to get the filename;
}
Calling JS to update the form's action attribute:
<body onLoad="setFormAction();">
Form tag with the submit button:
<form method="get" id="myDownloadButtonForm" action="">
Click to open document:
<button type="submit">Open Document</button>
</form>
The following did NOT work:
<form method="get" id="myDownloadButtonForm" action="javascript:someFunctionToReturnFileName();">

If you can't use form, another approach with downloadjs fit nice. Downloadjs use blob and html 5 file API under the hood:
<div onClick=(()=>{downloadjs(url, filename)})/>
*it's jsx/react syntax, but can be used in pure html

Not really an answer to the original question but it may help others which face similar situations as myself.
If the file you want to download is not hosted on the same origin but you want to be able to download it, you can do that with the Content-Disposition header. Make sure the server includes the header when responding to requests of the file.
Setting a value like
Content-Disposition: attachment will ensure that the file will be downloaded instead of viewed in the browser.
A simple Download pointing to your file should download it in this case.

If you want
Download
for the ability to download files that would be rendered by the browser otherwise, But still want a neat javascript function to use in a button; you can have an invisible link in html and click it in javascript.
function download_file() {
document.getElementById("my_download").click()
}
<a id="my_download" href="path_to_file" download="file_name" style="display:none;"></a>
<button onClick="download_file()">Download!!!</button>

Another way of doing in case you have a complex URL such as file.doc?foo=bar&jon=doe is to add hidden field inside the form
<form method="get" action="file.doc">
<input type="hidden" name="foo" value="bar" />
<input type="hidden" name="john" value="doe" />
<button type="submit">Download Now</button>
</form>
inspired on #Cfreak answer which is not complete

The solution I have come up with is that you can use download attribute in anchor tag but it will only work if your html file is on the server. but you may have a question like while designing a simple html page how can we check that for that you can use VS code live server or bracket live server and you will see your download attribute will work but if you will try to open it simply by just double clicking html page it open the file instead of downloading it.
conclusion: attribute download in anchor tag only works if your html file is no server.

For me ading button instead of anchor text works really well.
<button>Download!</button>
It might not be ok by most rules, but it looks pretty good.

If you use the <a> tag, do not forget to use the entire url which leads to the file -- i.e.:
Download

Related

How To make it so when you click an html button, it downloads a file to the persons computer?

<button type="submit" class="myButton" onclick="window.open('test.txt')">Money Dispenser</button>
Is the current code i have, and does not do anything at all when i click it. ( I want it to download test.txt to the computer or device of the user who cliked it)
I don't really understand what you are trying to achieve using a submit button, if it's not mandatory I'd use an <a>.
With pure HTML5 using the download attribute
<a href="test.txt" download>Money Dispenser</a>
Or with Javascript if you have to use a <button>
This has already been covered grealy in this question
But the gist of it is, create a function to download files as shown on that thread and add it to your <button>
<button onclick="donwloaURI('data:text/plain,Test', 'Test.txt')">Money Dispenser</button>
You can use the HTML download attribute to specify that the target will be downloaded when a user clicks on the hyperlink.
<a href="/download-file-path-here" download>
Money Dispenser
</a>
You can do using:
<a href="data:text/plain;charset=UTF-8,test.txt" download>Download</a>

How edit elements of existing link and open the edited version of the link? (Without saving it localy)

I want to build a html website_A where you can type some data and then open another website_B with a button click and this website_B would be changed according to the text we typed in the first website.
For example we have a website_B example.com with a
<h1 id="xxx">
We save the link in our website_A as a string, insert an input field and button with onClick function:
<input type="text" id="text_id" name="text_name"><br><br>
<input type="submit" value="Open Link!" onclick="openLink()">
<script>
var link = 'example.com';
function openLink() {
link.getElementById("xxx").innerHTML = document.getElementById("text_id").text;
window.open(link);
</script>
}
It should open the link with the changed h1.
Somehow it doesn't work, I don't know the javascript much, not even sure if I can achieve it with js or I have to use some othere languages. I googled a lot and didn't find anything, most information is about changing files locally or changing just the href link, not its elements.
I appreciate your help!

Javascript to print my pdf file

In my tomcat webapps folder contain one PDF I need to button press to new window show the file and print option open using JavaScript Is possible or any other way?
function print() {
var file = window.open('http://url/to/pdf');
file.print();
}
<input type="button" value="Print" onclick=print()>
I believe this is possible. Determine the url of the pdf on the tomcat web container and then the following JavaScript should work:
var pdfWin = window.open('MyPDF.pdf', '_blank', 'fullscreen=yes');
pdfWin.focus();
pdfWin.print();

open file using jQuery

I try to open a file using jQuery. Here is my HTML,
<button onclick='load();'>load</button>
Here is my js code:
function load() {
var fileSelector = $('<input id="load" type = "file" multiple />');
fileSelector.click();
//code here to get the files ...
}
Now I want to get the loaded files, what should I do?
The HTML5 File Api (http://dev.w3.org/2006/webapi/FileAPI/) allows opening files, however the files must be selected by the User for security.
If you need to open a file without user interaction, then it is necessary to do this on the server side with a language like PHP for example.
Here's my solution
I used the file type input and then use the Jquery trigger function to trigger the click event for file input.
$(function(){
$("#btnFile").click(function(){
$("#file").trigger("click");
});
});
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input id="file" type="file" hidden/>
<button id="btnFile">Click Me</button>
You can open JSON file with JavaScript and use fetch('json_file patch') .

javascript file download

I need to download a file (test.xml) and allow/prompt user to save the file on click on download button. The file resides in url "http://localhost/test/test.xml" .
I have added html code
<input type=button value="Download" onclick='javascript:download()/>
and javascript code is
function download() {
var url = "http://localhost/test/test.xml";
window.open(url, 'Download');
}
But this opens the page in new window. How do I prompt to download and save the file. Any inputs will be of help. Thanks
You have to change the content type in the header. You need to do some server scripting or configurate your webserver.
I Googled a link that will help you in the right direction: http://www.boutell.com/newfaq/creating/forcedownload.html
Using you inital code, if you have access to the backend, when the xml is requested, add the following header with it:
Content-disposition: attachment; filename=test.xml;
Another route would be to use xmlhttprequest to get the file, then use a flash plugin to save it. I've used this method a bit, and the flash swf can be found here
set the content type for the response header of the xml to be application/xml
html:
<input id="downloadthis" value="Download"/>
inside javascript tag:
$('#downloadthis').click( function() {
window.location.href = 'http://localhost/test/test.xml';
} );
REF: https://stackoverflow.com/a/4864264/405117

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