is there any 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 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, just assuming i already have full permissions to these files.
If you're deploying on Windows, the Windows Script Host offers a very useful JScript API to the file system and other local resources. Incorporating WSH scripts into a local web application may not be as elegant as you might wish, however.
on Firefox you (the programmer) can do this from within a javascript file:
netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserRead"); netscape.security.PrivilegeManager.enablePrivilege("UniversalBrowserWrite");
and you (the browser user) will be prompted to allow access. (for Firefox you just need to do this once every time the browser is started)
If the browser user is someone else, they have to grant permission.
In general, this is not allowed by design. It's a violation of the sandbox.
From Wikipedia -> Javascript -> Security:
JavaScript and the DOM provide the potential for malicious authors to deliver scripts to run on a client computer via the web. Browser authors contain this risk using two restrictions. First, scripts run in a sandbox in which they can only perform web-related actions, not general-purpose programming tasks like creating files.
You may want to take a look at the source code of tiddlywiki.
It uses browser specific methods to save it's modified instance into the local filesystem.
I am currently looking into the best way to do this. The code supplied by Jason S seems to be valid but the script needs to be digitally signed. I'm not sure if a self-signed cert will work here, or if it will generate some kind of error. Only digitally signed scripts can elevate permissions, otherwise it is just denied (you get something like "A script from "http://darktower.eondream.com" was denied UniversalXPConnect privileges.")
I haven't looked into this on IE yet. I wouldn't be terribly surprised to find a similar situation where only digitally signed code can elevate privileges.
Here is the firefox page about digitally signed scripts: http://www.mozilla.org/projects/security/components/signed-scripts.html
http://www.mozilla.org/projects/security/components/signed-scripts.html
You need not digitally sign the script, if the user enables signed.applets.codebase_principal_support (In about:config set the value to true)
This is explained in the same page under the heading Codebase Principals