Write To A File Without External Js Libraries (pure Javascript) In A Browser ?

Is it possible to write a string to a file (create the file if it doesn't exist) without any external Javascript libraries , purely with Javascript code ? I'm trying to implement

Solution 1:

As said in the comments, what you sound to try to achieve is intentionally very restricted for obvious security reasons of the visitor's machine.

Now "workarounds" could exist, depending on the actual objective you are trying to achieve (but which you did not mention).

• Cookies to store simple data (like your strings) in the visitor's computer (so strictly speaking, it does the job you ask for, but you have no control on which text file is used).
• Use a browser extension, which would have the permission to write on the visitor's filesystem. Applicable if you can get visitors to install such extension (e.g. if you are IT and can request employees installing specific software).
• localStorage as proposed in IanKenney's comment, if you just want some persistent data.