is it possible to read a file using javascript?

Hi all i just want to know if we can read a file using javascript like

what we do

fp=("r","path")

like th开发者_高级运维at is it possible?

---

No, that's not possible in a browser. Javascript runs in a sandboxed environment and doesn't have access to the file system. You might need to special plugins to be installed on the client browser in order to access his file system.

---

Yes, this is possible, even in some browsers.

Reading a local file, from a browser

If the browser supports the new File API, you can read any file the user gives you permission to read via an input[type=file] element. Specification | Example here on StackOverflow

Read a server file, from a browser

This can be done on all major browsers using "ajax", more specifically the XMLHttpRequest object. It's made a lot easier by libraries like jQuery, Prototype, YUI, Closure, or any of several others.

On a server, workstation, etc. (not in a browser)

You'll need an environment that provides file reading, such as NodeJS.

---

Firstly I think its not a good idea to read a file locally with JavaScript. I recommend first upload it to the server and then perform the reading.

Having said that it is possible, but you restricted by what you can do.

Im assuming its a local file on the user machine, otherwise AJAX would achieve this for a server read.

It might be possible through

1. Windows Script Host Object Model(WScript.Shell) and when granted Prompt or Enable access to ActiveX the browser has elevated privileges (Enable through Tools > Internet Options > Security > Custom Level ... > Set Active X settings to prompt). If this is still to difficult, user could download something thats installed and then does the reading through Shell Scripting! Disclaimer: Note I do not recommend this approach. Its not active for a reason and its so DIRTY (I feel dirty)!

2. Cookies might also be worth considering. If you can store the information in a cookie the JavaScript would be able to read, write and update it.

   Found this code from http://www.quirksmode.org/js/cookies.html scroll right to the bottom for the example.

   function createCookie(name,value,days) {
   if (days) {
       var date = new Date();
       date.setTime(date.getTime()+(days*24*60*60*1000));
       var expires = "; expires="+date.toGMTString();
   }
   else var expires = "";
   document.cookie = name+"="+value+expires+"; path=/";
   

   }

   function readCookie(name) {
       var nameEQ = name + "=";
       var ca = document.cookie.split(';');
       for(var i=0;i < ca.length;i++) {
           var c = ca[i];
           while (c.charAt(0)==' ') c = c.substring(1,c.length);
           if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
       }
       return null;
   }
   
   function eraseCookie(name) {
       createCookie(name,"",-1);
   }
   

---

Reading from client: how to read a text file using Javascript

Reading from server: jquery - Read a text file?

---

Reading client files in javascript is possible with the new File API available in modern browsers. Check this site and its code: http://www.readfileonline.com/

---

You can but then you have to use AJAX, which is Javascript for server side jobs.