Javascript browser download large file

The button click event triggers the file input click event and displays the file picker. After you select files and close the dialog box, the input event occurs and the uploadFiles function is called.

This function creates a BlockBlobClient object, then calls the browser-only uploadBrowserData function for each file you selected. Each call returns a Promise. Each Promise is added to a list so that they can all be awaited together, causing the files to upload in parallel. Delete files from the storage container when you click the Delete selected files button.

It then calls the listFiles function shown earlier to refresh the contents of the Files list. To run the code inside the Visual Studio Code debugger, configure the launch. Adding a new configuration creates a launch. Modify the launch. After updating, save the launch. Changes you make to index. In the launch. Run the page in the debugger and get a feel for how blob storage works.

If any errors occur, the Status pane on the web page will display the error message received. To open index. In the Azure portal , you can verify the results of the API calls as you follow the steps below. To clean up the resources created during this quickstart, go to the Azure portal and delete the resource group you created in the Prerequisites section. In this quickstart, you learned how to upload, list, and delete blobs using JavaScript.

Webix suggests a ready-made solution, which is JS File manager, that can be built into any web application. File explorer is an in-demand UI component, which can be used in various UX cases, as it contains all necessary elements for working with lists of objects: search, sorting, table and tile views.

Also, Webix widget has double panels view to work with files in the "old school" mode. Traditional UI for working with files catalog tree, table and tile arrangement of the files , dual panel and previewing. A build-in manager of the uploads, an opportunity to download and upload files with one click or with the help of drag-n-drop.

Explore supplied code samples to get the idea of how File Manager JS widget can be used in web applications. Close Menu. Windows and popups Context Popup Tooltip Window. Servers that already serve. This is OK if you are using such an environment already, or if you aren't but you know what you are doing and have access i.

It could however cause confusion if you don't control the server you are serving files from, or are publishing files for public use, as we are here. If you really value the clarity of using. The first thing you do to get access to module features is export them. This is done using the export statement. The easiest way to use it is to place it in front of any items you want exported out of the module, for example:. You can export functions, var , let , const , and — as we'll see later — classes.

They need to be top-level items; you can't use export inside a function, for example. A more convenient way of exporting all the items you want to export is to use a single export statement at the end of your module file, followed by a comma-separated list of the features you want to export wrapped in curly braces.

For example:. Once you've exported some features out of your module, you need to import them into your script to be able to use them. May be that for others though so worth the read.

Do you think that it will, or cookies restrictions will compromise it? Brilliant - it wouldn't have occurred to me in years that you could include cookies as part of a file download. Thank you!! As others have pointed out, this solution only solves part of the problem, the waiting for the server to prepare the file time. The other part of the problem, which can be considerable depending on the size of the file and the connection speed, is how long it takes to actually get the whole file on the client.

And that is not solved with this solution. Show 16 more comments. Echilon 9, 28 28 gold badges silver badges bronze badges.

This is a simple approach which is ideal for getting rid of a loading overlay for a file download which was triggered using onbeforeunload Thank you. Safari, some IE versions, etc. Chrome and other such browsers auto-download the files where this condition will fail. Lucky that is only by default. It is entirely possible a user of Chrome will specify where downloads should be saved and hence see the dialog box — ESR. Add a comment. Don't eval code inside setTimeout 'getstatus ', ;. Use the fn directly: setTimeout getstatus, ; — Roko C.

Jerzy Gebler Jerzy Gebler 9 9 silver badges 13 13 bronze badges. What if the user clicks the window? The hide is not getting called in my case — Prashant Pimpale. Worked for me for a pdf download with only some line of codes — Chris. My case is working on JSP and click to download csv. It works. Show 1 more comment. There are four known approaches to dealing with detecting when a browser download starts: Call fetch , retrieve the entire response, attach an a tag with a download attribute, and trigger a click event.

Modern web browsers will then offer the user the option to save the already retrieved file. There are several downsides with this approach: The entire data blob is stored in RAM, so if the file is large, it will consume that much RAM. For small files, this probably isn't a deal breaker. The user has to wait for the entire file to download before they can save it. They also can't leave the page until it completes. The built-in web browser file downloader is not used. A cross-domain fetch will probably fail unless CORS headers are set.

The iframe fires a load event if a page loads in the iframe instead of starting a download but it does not fire any events if the download starts.

Setting a cookie with the web server can then be detected by Javascript in a loop. There are several downsides with this approach: The server and client have to work in concert. The server has to set a cookie. The client has to detect the cookie. Cross-domain requests won't be able to set the cookie. There are limits to how many cookies can be set per domain. Can't send custom HTTP headers. Use an iframe with URL redirection.

The iframe starts a request and once the server has prepared the file, it dumps a HTML document that performs a meta refresh to a new URL, which triggers the download 1 second later. The load event on the iframe happens when the HTML document loads.

There are several downsides with this approach: The server has to maintain storage for the content being downloaded. Requires a cron job or similar to regularly clean up the directory. The server has to dump out special HTML content when the file is ready. The client has to guess as to when the iframe has actually made the second request to the server and when the download has actually started before removing the iframe from the DOM. This could be overcome by just leaving the iframe in the DOM.

The iframe triggers the download request. As soon as the request is made via the iframe, an identical request via XHR is made. If the load event on the iframe fires, an error has occurred, abort the XHR request, and remove the iframe.

If a XHR progress event fires, then downloading has probably started in the iframe, abort the XHR request, wait a few seconds, and then remove the iframe. This allows for larger files to be downloaded without relying on a server-side cookie. There are several downsides with this approach: There are two separate requests made for the same information.

The server can distinguish the XHR from the iframe by checking the incoming headers. If the server waits to send headers until the file data is ready, the XHR can roughly detect when the iframe has started to download even without CORS. The client has to guess as to when the download has actually started to remove the iframe from the DOM. Can't send custom headers on the iframe. CubicleSoft CubicleSoft 1, 15 15 silver badges 18 18 bronze badges. Elmer Elmer 8, 1 1 gold badge 44 44 silver badges 35 35 bronze badges.

Still has the issue of switching window and returning which will cause the modal to hide. JQuery is supported but not required.