Javascript write to file and download

I've created an updated example that uses this technique. If you are talking about browser javascript, you can not write data directly to local file for security reason. But if you want to write data, and enable user to download as a file to local. If you want to download binary data look here. Above answer is useful but, I found code which helps you to download text file directly on button click.

In this code you can also change filename as you wish. It's pure javascript function with HTML5. Works for me! In the case it is not possibile to use the new Blob solution, that is for sure the best solution in modern browser, it is still possible to use this simpler approach, that has a limit in the file size by the way:.

By default it will make. If you want to download the file automatically, pass the textFile that was just generated to this function:. The button to create the blob and the download link can be combined in one link, as the link element can have an onclick attribute. The reverse seems not possible, adding a href to a button does not work. You can style the link as a button using bootstrap , which is still pure javascript, except for styling. Combining the button and the download link also reduces code, as fewer of those ugly getElementById calls are needed.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Is it possible to write data to file using only JavaScript? Ask Question. Asked 7 years, 10 months ago. Active 1 year, 3 months ago. Viewed k times. I referred the code but its not working: its giving error: Uncaught TypeError: Illegal constructor on chrome and SecurityError: The operation is insecure.

Improve this question. BeWu 1, 1 1 gold badge 14 14 silver badges 21 21 bronze badges. This time, we are using a JavaScript library called FileSaver. The example below presents the syntax to implement the saveAs FileSaver interface:. It sets the file to a Blob value. For instance, it is useful for preventing sensitive information from being sent to external servers. It includes but is not limited to multimedia objects , programs , and code snippets. Remember: as Blob has size limitations based on the supported browser, FileSaver.

See the table below to check the compatibility of FileSaver. Learn easily by using our HTML5 canvas examples. Learn Bootstrap: this Bootstrap 4 tutorial will easily teach you how to use it for your mobile web design.

Learn Bootstrap quickly to become a master. Code has been added to clipboard! Reading time 3 min. However, this is not supported by other browsers. If you are not limited to browser, Node.

See here for its file system documentation. Note that Node. The javascript test runner Karma is based on Node. If you just like to program in javascript on the local computer, this is an option. Create your directory in the C drive because windows has security against writing from web e. You'll have to turn to Flash, Java or Silverlight.

In the case of Silverlight, you'll be looking at Isolated Storage. That will get you write to files in your own playground on the users disk. It won't let you write outside of your playground though.

You can't do this in any cross-browser way. Writing this answer for people who wants to get a file to download with specific content from javascript. I was struggling with the same thing. Best suited for writing large data generated on client side. Otherwise I suggest using FileSaver. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. How to read and write into file using JavaScript? Ask Question. Asked 12 years, 9 months ago.

Active 1 year, 3 months ago. Viewed k times. Can anybody give some sample code to read and write a file using JavaScript? Improve this question. Sebastian Simon Why do you need it? Maybe there are workarounds. I found this resource regarding client-side file storage. The browser manages the file storage and imposes certain limits to prevent the World Wide Web from loading peoples hard drives down to the brim. They're not completely fool proof yet, but they're being tweaked, at least according to this article.

As you can see above, the download attribute is the easiest way to download a file on the browser. However, the download attribute only works in modern browsers. Internet Explorer does not support it. The idea is to programmatically create an anchor link, and then trigger the click event. This method is especially helpful for dynamically generated file URLs. Sometimes, you may want to save programmatically generated data as a file using JavaScript.