diff --git a/4chan_x.user.js b/4chan_x.user.js
index 76833955a..77dbb7e7d 100644
--- a/4chan_x.user.js
+++ b/4chan_x.user.js
@@ -1249,7 +1249,9 @@
     error: function(err) {
       $('.error', qr.el).textContent = err;
       qr.open();
-      return alert(err);
+      if (d.hidden || d.oHidden || d.mozHidden || d.webkitHidden) {
+        return alert(err);
+      }
     },
     cleanError: function() {
       return $('.error', qr.el).textContent = null;
@@ -1432,8 +1434,10 @@
         if (!(response = this.input.value)) return;
         captchas = $.get('captchas', []);
         now = Date.now();
-        while (captchas[0].time < now) {
-          captchas.shift();
+        if (captchas.length) {
+          while (captchas[0].time < now) {
+            captchas.shift();
+          }
         }
         length = captchas.push({
           challenge: this.challenge.firstChild.value,
@@ -1529,13 +1533,51 @@
       return $.add(d.body, qr.el);
     },
     submit: function(e) {
+      var captcha, captchas, challenge, err, len, m, now, reply, response, resto;
       if (e != null) e.preventDefault();
-      if (g.dead) return;
-      if (conf['Auto Hide QR']) {
+      reply = qr.replies[0];
+      if (!(reply.com || reply.file)) {
+        err = 'Error: No file selected.';
+      } else {
+        captchas = $.get('captchas', []);
+        if (len = captchas.length) {
+          now = Date.now();
+          while (captchas[0].time < now) {
+            captchas.shift();
+          }
+        }
+        if (captcha = captchas.shift()) {
+          challenge = captcha.challenge;
+          response = captcha.response;
+        } else {
+          challenge = qr.captcha.img.alt;
+          if (response = qr.captcha.input.value) qr.captcha.reload();
+        }
+        $.set('captchas', captchas);
+        qr.captcha.count(captchas.length);
+        if (!response) err = 'Error: No valid captcha.';
+      }
+      if (err) {
+        qr.error(err);
+        return;
+      }
+      qr.cleanError();
+      if (conf['Auto Hide QR'] && qr.replies.length === 1) {
         $.id('autohide').checked = true;
         qr.hide();
       }
-      return qr.cleanError();
+      return qr.message.send({
+        resto: g.REPLY ? g.THREAD_ID : (resto = $('select').value !== 'new') ? resto : void 0,
+        name: reply.name,
+        email: reply.email,
+        sub: reply.sub,
+        com: reply.com,
+        file: reply.file,
+        mode: 'regist',
+        pwd: (m = d.cookie.match(/4chan_pass=([^;]+)/)) ? decodeURIComponent(m[1]) : $('input[name=pwd]').value,
+        recaptcha_challenge_field: challenge,
+        recaptcha_response_field: response
+      });
     },
     response: function(e) {
       var reply, sage;
diff --git a/script.coffee b/script.coffee
index bebc60b93..612baa732 100644
--- a/script.coffee
+++ b/script.coffee
@@ -910,7 +910,7 @@ qr =
   error: (err) ->
     $('.error', qr.el).textContent = err
     qr.open()
-    alert err
+    alert err if d.hidden or d.oHidden or d.mozHidden or d.webkitHidden
   cleanError: ->
     $('.error', qr.el).textContent = null
 
@@ -1064,8 +1064,9 @@ qr =
       captchas = $.get 'captchas', []
       # remove old captchas
       now = Date.now()
-      while captchas[0].time < now
-        captchas.shift()
+      if captchas.length
+        while captchas[0].time < now
+          captchas.shift()
       length = captchas.push
         challenge: @challenge.firstChild.value
         response:  response
@@ -1153,12 +1154,55 @@ qr =
 
   submit: (e) ->
     e?.preventDefault()
-    return if g.dead
-    if conf['Auto Hide QR'] # and only one post (left) to submit
+    reply = qr.replies[0]
+
+    # prevent errors
+    unless reply.com or reply.file
+      err = 'Error: No file selected.'
+    else
+      # get oldest valid captcha
+      captchas = $.get 'captchas', []
+      if len = captchas.length
+        # remove old captchas
+        now = Date.now()
+        while captchas[0].time < now
+          captchas.shift()
+      if captcha  = captchas.shift()
+        challenge = captcha.challenge
+        response  = captcha.response
+      else
+        challenge    = qr.captcha.img.alt
+        if response  = qr.captcha.input.value then qr.captcha.reload()
+      $.set 'captchas', captchas
+      qr.captcha.count captchas.length
+      unless response
+        err = 'Error: No valid captcha.'
+
+    # more error prevention ?
+    if err
+      qr.error err
+      return
+    qr.cleanError()
+
+    if conf['Auto Hide QR'] and qr.replies.length is 1
       $.id('autohide').checked = true
       qr.hide()
-    qr.cleanError()
-    # magical xhr2
+
+    qr.message.send
+      resto:
+        if g.REPLY
+          g.THREAD_ID
+        else if resto = $('select').value isnt 'new'
+          resto
+      name:  reply.name
+      email: reply.email
+      sub:   reply.sub
+      com:   reply.com
+      file:  reply.file
+      mode:  'regist'
+      pwd: if m = d.cookie.match(/4chan_pass=([^;]+)/) then decodeURIComponent m[1] else $('input[name=pwd]').value
+      recaptcha_challenge_field: challenge
+      recaptcha_response_field:  response
 
   response: (e) ->
     log e
@@ -1199,7 +1243,7 @@ qr =
       $.rm script
     send: (data) ->
       data.changeContext = true
-      data.qr = true
+      data.qr            = true
       postMessage data, '*'
     receive: (data) ->
       log 'receive', location.hostname, data