How to read and write into file using JavaScript?

Question

Can anybody give some sample code to read and write a file using JavaScript?

Answer 1

This Javascript function presents a complete "Save As" Dialog box to the user who runs this through the browser. The user presses OK and the file is saved.

Edit: The following code only works with IE Browser since Firefox and Chrome have considered this code a security problem and has blocked it from working.

// content is the data you'll write to file

// filename is the filename

// what I did is use iFrame as a buffer, fill it up with text
function save_content_to_file(content, filename)
{
    var dlg = false;
    with(document){
     ir=createElement('iframe');
     ir.id='ifr';
     ir.location='about.blank';
     ir.style.display='none';
     body.appendChild(ir);
      with(getElementById('ifr').contentWindow.document){
           open("text/plain", "replace");
           charset = "utf-8";
           write(content);
           close();
           document.charset = "utf-8";
           dlg = execCommand('SaveAs', false, filename+'.txt');
       }
       body.removeChild(ir);
     }
    return dlg;
}

Invoke the function:

save_content_to_file("Hello", "C:\\test");