diff --git a/program/blank.tif b/program/blank.tif
new file mode 100644
index 000000000..2b3f4ec5d
Binary files /dev/null and b/program/blank.tif differ
diff --git a/program/js/app.js b/program/js/app.js
index c4bf5ec31..32ab69f2e 100644
--- a/program/js/app.js
+++ b/program/js/app.js
@@ -307,6 +307,10 @@ function rcube_webmail()
           this.http_post(postact, postdata);
         }
 
+        // detect browser capabilities
+        if (!this.is_framed())
+          this.browser_capabilities_check();
+
         break;
 
       case 'addressbook':
@@ -1943,13 +1947,16 @@ function rcube_webmail()
     if (this.env.search_request)
       url += '&_search='+this.env.search_request;
 
-    if (action == 'preview' && String(target.location.href).indexOf(url) >= 0)
+    // add browser capabilities, so we can properly handle attachments
+    url += '&_caps='+urlencode(this.browser_capabilities());
+
+    if (preview && String(target.location.href).indexOf(url) >= 0)
       this.show_contentframe(true);
     else {
       this.location_href(this.env.comm_path+url, target, true);
 
       // mark as read and change mbox unread counter
-      if (action == 'preview' && this.message_list && this.message_list.rows[id] && this.message_list.rows[id].unread && this.env.preview_pane_mark_read >= 0) {
+      if (preview && this.message_list && this.message_list.rows[id] && this.message_list.rows[id].unread && this.env.preview_pane_mark_read >= 0) {
         this.preview_read_timer = setTimeout(function() {
           ref.set_message(id, 'unread', false);
           ref.update_thread_root(id, 'read');
@@ -6368,6 +6375,78 @@ function rcube_webmail()
       $(elem).click(function() { rcmail.register_protocol_handler(name); return false; });
   };
 
+  // Checks browser capabilities eg. PDF support, TIF support
+  this.browser_capabilities_check = function()
+  {
+    if (!this.env.browser_capabilities)
+      this.env.browser_capabilities = {};
+
+    if (this.env.browser_capabilities.pdf === undefined)
+      this.env.browser_capabilities.pdf = this.pdf_support_check();
+
+    if (this.env.browser_capabilities.tif === undefined)
+      this.tif_support_check();
+  };
+
+  // Returns browser capabilities string
+  this.browser_capabilities = function()
+  {
+    if (!this.env.browser_capabilities)
+      return '';
+
+    var n, ret = [];
+
+    for (n in this.env.browser_capabilities)
+      ret.push(n + '=' + this.env.browser_capabilities[n]);
+
+    return ret.join();
+  };
+
+  this.tif_support_check = function()
+  {
+    var img = new Image();
+
+    img.onload = function() { rcmail.env.browser_capabilities.tif = 1; };
+    img.onerror = function() { rcmail.env.browser_capabilities.tif = 0; };
+    img.src = 'program/blank.tif';
+  };
+
+  this.pdf_support_check = function()
+  {
+    var plugin = navigator.mimeTypes ? navigator.mimeTypes["application/pdf"] : {},
+      plugins = navigator.plugins,
+      len = plugins.length,
+      regex = /Adobe Reader|PDF|Acrobat/i;
+
+    if (plugin && plugin.enabledPlugin)
+        return 1;
+
+    if (window.ActiveXObject) {
+      try {
+        if (axObj = new ActiveXObject("AcroPDF.PDF"))
+          return 1;
+      }
+      catch (e) {}
+      try {
+        if (axObj = new ActiveXObject("PDF.PdfCtrl"))
+          return 1;
+      }
+      catch (e) {}
+    }
+
+    for (i=0; i<len; i++) {
+      plugin = plugins[i];
+      if (typeof plugin === 'String') {
+        if (regex.test(plugin))
+          return 1;
+      }
+      else if (plugin.name && regex.test(plugin.name))
+        return 1;
+    }
+
+    return 0;
+  };
+
 }  // end object rcube_webmail
 
 
diff --git a/program/steps/mail/func.inc b/program/steps/mail/func.inc
index 05d589503..fb438c9ed 100644
--- a/program/steps/mail/func.inc
+++ b/program/steps/mail/func.inc
@@ -81,8 +81,8 @@ if (empty($RCMAIL->action) || $RCMAIL->action == 'list') {
       $OUTPUT->set_env('search_request', $search_request);
     }
 
-      $search_mods = $RCMAIL->config->get('search_mods', $SEARCH_MODS_DEFAULT);
-      $OUTPUT->set_env('search_mods', $search_mods);
+    $search_mods = $RCMAIL->config->get('search_mods', $SEARCH_MODS_DEFAULT);
+    $OUTPUT->set_env('search_mods', $search_mods);
   }
 
   $threading = (bool) $RCMAIL->storage->get_threading();
@@ -115,6 +115,9 @@ if (empty($RCMAIL->action) || $RCMAIL->action == 'list') {
   if ($CONFIG['junk_mbox'])
     $OUTPUT->set_env('junk_mailbox', $CONFIG['junk_mbox']);
 
+  if (!empty($_SESSION['browser_caps']))
+    $OUTPUT->set_env('browser_capabilities', $_SESSION['browser_caps']);
+
   if (!$OUTPUT->ajax_call)
     $OUTPUT->add_label('checkingmail', 'deletemessage', 'movemessagetotrash',
       'movingmessage', 'copyingmessage', 'deletingmessage', 'markingmessage',
diff --git a/program/steps/mail/show.inc b/program/steps/mail/show.inc
index 2d4d8e5a5..a104880ca 100644
--- a/program/steps/mail/show.inc
+++ b/program/steps/mail/show.inc
@@ -21,6 +21,16 @@
 
 $PRINT_MODE = $RCMAIL->action=='print' ? TRUE : FALSE;
 
+// Read browser capabilities and store them in session
+if ($caps = get_input_value('_caps', RCUBE_INPUT_GET)) {
+  $browser_caps = array();
+  foreach (explode(',', $caps) as $cap) {
+    $cap = explode('=', $cap);
+    $browser_caps[$cap[0]] = $cap[1];
+  }
+  $_SESSION['browser_caps'] = $browser_caps;
+}
+
 // similar code as in program/steps/mail/get.inc
 if ($uid = get_input_value('_uid', RCUBE_INPUT_GET)) {
   $MESSAGE = new rcube_message($uid);