Local JavaScript - write to local file

Question

I have some JavaScript code loaded from a local HTML file (without going through a webserver).. i.e., opened using file://

Is there a way the JavaScript code in this file can be used to write to a local file?

I know that cross-site restrictions do not allow lot of things in JavaScript, but this is not cross-site, so it should be allowed in theory.

possible duplicate of [Self modifying html-JavaScript file](http://stackoverflow.com/questions/3854059/self-modifying-html-javascript-file) — Joachim Breitner, Oct 20 '13 at 17:07

score 11 · Accepted Answer · answered Mar 18 '11 at 09:10

11

There's a jQuery plugin jQuery.twFile that allows you to read and write to a local file.

answered Mar 18 '11 at 09:10

Diogo Cardoso

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The link in this answer is broken. Is this plugin still available? – Anderson Green Feb 15 '22 at 22:23

score 4 · Answer 2 · edited Aug 24 '16 at 15:22

4

In case of Internet Explorer you can use ActiveX.

<html>
    <head>
        <script type="text/javaScript">
            function WriteToFile()
            {
               var fso  = new ActiveXObject("Scripting.FileSystemObject");
               var txtFile = fso.CreateTextFile("c:\\TestFile.txt", true);
               txtFile.WriteLine("This is a test");
               txtFile.Close();
            }
        </script>
    </head>

    <body>
        <p>
            <script type="text/javaScript">  WriteToFile(); </script>
        </p>
    </body>
</html>

edited Aug 24 '16 at 15:22

Peter Mortensen

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answered Mar 18 '11 at 09:16

Ashwin Krishnamurthy

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the activeX idea is good but I need the page to work in Firefox too – Jus12 Mar 18 '11 at 09:19
1

Perhaps a firefox extension would do you some good. Check this out https://developer.mozilla.org/en/Code_snippets/File_I%2F%2FO – Ashwin Krishnamurthy Mar 18 '11 at 09:27
ActiveX? So it only works on Windows? What about the security implications? – Peter Mortensen Aug 24 '16 at 15:23

Lee Kowalkowski · Answer 3 · 2013-11-13T20:51:19.443

0

There's no native API* for File System access in browsers. You need that first!

For example, in Internet Explorer, there's an ActiveX object for it:

var fso = new ActiveXObject("Scripting.FileSystemObject");

...but it requires the user to relax their browser settings. On other browsers, you may be able to use a jar (Java Archive) file.

You could also see what non-browser JavaScript containers offer, e.g. Microsoft HTA files (HTML Application) will support the Windows ActiveX FileSystemObject fine, providing your Virus Checking Software allows HTA files to execute.

edited Nov 13 '13 at 20:51

answered Mar 18 '11 at 09:18

Lee Kowalkowski

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* APIs now exist, but good support is still lacking: http://caniuse.com/#feat=filesystem – Lee Kowalkowski Nov 13 '13 at 20:51

Local JavaScript - write to local file

3 Answers3

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