Is there local file manipulation that's been done with JavaScript? I'm looking for a solution that can be accomplished with no install footprint like requiring Adobe AIR.
Specifically, I'd like to read the contents from a file and write those contents to another file. At this point I'm not worried about gaining permissions and am just assuming I already have full permissions to these files.
Assuming that any file that JavaScript code might need, should be allowed directly by the user. Creators of famous browsers do not let JavaScript access files generally.
The main idea of the solution is: the JavaScript code cannot access the file by having its local URL. But it can use the file by having its DataURL: so if the user browses a file and opens it, JavaScript should get the "DataURL" directly from HTML instead of getting "URL".
Then it turns the DataURL into a file, using the readAsDataURL function and FileReader object. Source and a more complete guide with a nice example are in: