diff --git a/web/thumbnail_view.js b/web/thumbnail_view.js
new file mode 100644
index 000000000..c963e2e6b
--- /dev/null
+++ b/web/thumbnail_view.js
@@ -0,0 +1,191 @@
+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
+/* Copyright 2012 Mozilla Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/* globals PDFView, mozL10n, RenderingStates */
+
+'use strict';
+
+var ThumbnailView = function thumbnailView(container, id, defaultViewport) {
+  var anchor = document.createElement('a');
+  anchor.href = PDFView.getAnchorUrl('#page=' + id);
+  anchor.title = mozL10n.get('thumb_page_title', {page: id}, 'Page {{page}}');
+  anchor.onclick = function stopNavigation() {
+    PDFView.page = id;
+    return false;
+  };
+
+  this.pdfPage = undefined;
+  this.viewport = defaultViewport;
+  this.pdfPageRotate = defaultViewport.rotate;
+
+  this.rotation = 0;
+  this.pageWidth = this.viewport.width;
+  this.pageHeight = this.viewport.height;
+  this.pageRatio = this.pageWidth / this.pageHeight;
+  this.id = id;
+
+  this.canvasWidth = 98;
+  this.canvasHeight = this.canvasWidth / this.pageWidth * this.pageHeight;
+  this.scale = (this.canvasWidth / this.pageWidth);
+
+  var div = this.el = document.createElement('div');
+  div.id = 'thumbnailContainer' + id;
+  div.className = 'thumbnail';
+
+  if (id === 1) {
+    // Highlight the thumbnail of the first page when no page number is
+    // specified (or exists in cache) when the document is loaded.
+    div.classList.add('selected');
+  }
+
+  var ring = document.createElement('div');
+  ring.className = 'thumbnailSelectionRing';
+  ring.style.width = this.canvasWidth + 'px';
+  ring.style.height = this.canvasHeight + 'px';
+
+  div.appendChild(ring);
+  anchor.appendChild(div);
+  container.appendChild(anchor);
+
+  this.hasImage = false;
+  this.renderingState = RenderingStates.INITIAL;
+
+  this.setPdfPage = function thumbnailViewSetPdfPage(pdfPage) {
+    this.pdfPage = pdfPage;
+    this.pdfPageRotate = pdfPage.rotate;
+    this.viewport = pdfPage.getViewport(1);
+    this.update();
+  };
+
+  this.update = function thumbnailViewUpdate(rot) {
+    if (!this.pdfPage) {
+      return;
+    }
+
+    if (rot !== undefined) {
+      this.rotation = rot;
+    }
+
+    var totalRotation = (this.rotation + this.pdfPage.rotate) % 360;
+    this.viewport = this.viewport.clone({
+      scale: 1,
+      rotation: totalRotation
+    });
+    this.pageWidth = this.viewport.width;
+    this.pageHeight = this.viewport.height;
+    this.pageRatio = this.pageWidth / this.pageHeight;
+
+    this.canvasHeight = this.canvasWidth / this.pageWidth * this.pageHeight;
+    this.scale = (this.canvasWidth / this.pageWidth);
+
+    div.removeAttribute('data-loaded');
+    ring.textContent = '';
+    ring.style.width = this.canvasWidth + 'px';
+    ring.style.height = this.canvasHeight + 'px';
+
+    this.hasImage = false;
+    this.renderingState = RenderingStates.INITIAL;
+    this.resume = null;
+  };
+
+  this.getPageDrawContext = function thumbnailViewGetPageDrawContext() {
+    var canvas = document.createElement('canvas');
+    canvas.id = 'thumbnail' + id;
+
+    canvas.width = this.canvasWidth;
+    canvas.height = this.canvasHeight;
+    canvas.className = 'thumbnailImage';
+    canvas.setAttribute('aria-label', mozL10n.get('thumb_page_canvas',
+      {page: id}, 'Thumbnail of Page {{page}}'));
+
+    div.setAttribute('data-loaded', true);
+
+    ring.appendChild(canvas);
+
+    var ctx = canvas.getContext('2d');
+    ctx.save();
+    ctx.fillStyle = 'rgb(255, 255, 255)';
+    ctx.fillRect(0, 0, this.canvasWidth, this.canvasHeight);
+    ctx.restore();
+    return ctx;
+  };
+
+  this.drawingRequired = function thumbnailViewDrawingRequired() {
+    return !this.hasImage;
+  };
+
+  this.draw = function thumbnailViewDraw(callback) {
+    if (!this.pdfPage) {
+      var promise = PDFView.getPage(this.id);
+      promise.then(function(pdfPage) {
+        this.setPdfPage(pdfPage);
+        this.draw(callback);
+      }.bind(this));
+      return;
+    }
+
+    if (this.renderingState !== RenderingStates.INITIAL) {
+      console.error('Must be in new state before drawing');
+    }
+
+    this.renderingState = RenderingStates.RUNNING;
+    if (this.hasImage) {
+      callback();
+      return;
+    }
+
+    var self = this;
+    var ctx = this.getPageDrawContext();
+    var drawViewport = this.viewport.clone({ scale: this.scale });
+    var renderContext = {
+      canvasContext: ctx,
+      viewport: drawViewport,
+      continueCallback: function(cont) {
+        if (PDFView.highestPriorityPage !== 'thumbnail' + self.id) {
+          self.renderingState = RenderingStates.PAUSED;
+          self.resume = function() {
+            self.renderingState = RenderingStates.RUNNING;
+            cont();
+          };
+          return;
+        }
+        cont();
+      }
+    };
+    this.pdfPage.render(renderContext).then(
+      function pdfPageRenderCallback() {
+        self.renderingState = RenderingStates.FINISHED;
+        callback();
+      },
+      function pdfPageRenderError(error) {
+        self.renderingState = RenderingStates.FINISHED;
+        callback();
+      }
+    );
+    this.hasImage = true;
+  };
+
+  this.setImage = function thumbnailViewSetImage(img) {
+    if (this.hasImage || !img)
+      return;
+    this.renderingState = RenderingStates.FINISHED;
+    var ctx = this.getPageDrawContext();
+    ctx.drawImage(img, 0, 0, img.width, img.height,
+                  0, 0, ctx.canvas.width, ctx.canvas.height);
+
+    this.hasImage = true;
+  };
+};
diff --git a/web/viewer.html b/web/viewer.html
index b8a914d92..873de15a2 100644
--- a/web/viewer.html
+++ b/web/viewer.html
@@ -80,6 +80,7 @@ limitations under the License.
 <!--#if !PRODUCTION-->
     <script type="text/javascript" src="ui_utils.js"></script>
     <script type="text/javascript" src="download_manager.js"></script>
+    <script type="text/javascript" src="thumbnail_view.js"></script>
     <script type="text/javascript" src="text_layer_builder.js"></script>
     <script type="text/javascript" src="pdf_find_bar.js"></script>
     <script type="text/javascript" src="pdf_find_controller.js"></script>
diff --git a/web/viewer.js b/web/viewer.js
index 47e0a4cd5..0ae462779 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -17,7 +17,7 @@
 /* globals PDFJS, PDFBug, FirefoxCom, Stats, Cache, PDFFindBar, CustomStyle,
            PDFFindController, ProgressBar, TextLayerBuilder, DownloadManager,
            getFileName, getOutputScale, scrollIntoView, getPDFFileNameFromURL,
-           PDFHistory, noContextMenuHandler */
+           PDFHistory, ThumbnailView, noContextMenuHandler */
 
 'use strict';
 
@@ -1984,179 +1984,7 @@ var PageView = function pageView(container, id, scale,
   };
 };
 
-var ThumbnailView = function thumbnailView(container, id, defaultViewport) {
-  var anchor = document.createElement('a');
-  anchor.href = PDFView.getAnchorUrl('#page=' + id);
-  anchor.title = mozL10n.get('thumb_page_title', {page: id}, 'Page {{page}}');
-  anchor.onclick = function stopNavigation() {
-    PDFView.page = id;
-    return false;
-  };
-
-
-  this.pdfPage = undefined;
-  this.viewport = defaultViewport;
-  this.pdfPageRotate = defaultViewport.rotate;
-
-  this.rotation = 0;
-  this.pageWidth = this.viewport.width;
-  this.pageHeight = this.viewport.height;
-  this.pageRatio = this.pageWidth / this.pageHeight;
-  this.id = id;
-
-  this.canvasWidth = 98;
-  this.canvasHeight = this.canvasWidth / this.pageWidth * this.pageHeight;
-  this.scale = (this.canvasWidth / this.pageWidth);
-
-  var div = this.el = document.createElement('div');
-  div.id = 'thumbnailContainer' + id;
-  div.className = 'thumbnail';
-
-  if (id === 1) {
-    // Highlight the thumbnail of the first page when no page number is
-    // specified (or exists in cache) when the document is loaded.
-    div.classList.add('selected');
-  }
-
-  var ring = document.createElement('div');
-  ring.className = 'thumbnailSelectionRing';
-  ring.style.width = this.canvasWidth + 'px';
-  ring.style.height = this.canvasHeight + 'px';
-
-  div.appendChild(ring);
-  anchor.appendChild(div);
-  container.appendChild(anchor);
-
-  this.hasImage = false;
-  this.renderingState = RenderingStates.INITIAL;
-
-  this.setPdfPage = function thumbnailViewSetPdfPage(pdfPage) {
-    this.pdfPage = pdfPage;
-    this.pdfPageRotate = pdfPage.rotate;
-    this.viewport = pdfPage.getViewport(1);
-    this.update();
-  };
-
-  this.update = function thumbnailViewUpdate(rot) {
-    if (!this.pdfPage) {
-      return;
-    }
-
-    if (rot !== undefined) {
-      this.rotation = rot;
-    }
-
-    var totalRotation = (this.rotation + this.pdfPage.rotate) % 360;
-    this.viewport = this.viewport.clone({
-      scale: 1,
-      rotation: totalRotation
-    });
-    this.pageWidth = this.viewport.width;
-    this.pageHeight = this.viewport.height;
-    this.pageRatio = this.pageWidth / this.pageHeight;
-
-    this.canvasHeight = this.canvasWidth / this.pageWidth * this.pageHeight;
-    this.scale = (this.canvasWidth / this.pageWidth);
-
-    div.removeAttribute('data-loaded');
-    ring.textContent = '';
-    ring.style.width = this.canvasWidth + 'px';
-    ring.style.height = this.canvasHeight + 'px';
-
-    this.hasImage = false;
-    this.renderingState = RenderingStates.INITIAL;
-    this.resume = null;
-  };
-
-  this.getPageDrawContext = function thumbnailViewGetPageDrawContext() {
-    var canvas = document.createElement('canvas');
-    canvas.id = 'thumbnail' + id;
-
-    canvas.width = this.canvasWidth;
-    canvas.height = this.canvasHeight;
-    canvas.className = 'thumbnailImage';
-    canvas.setAttribute('aria-label', mozL10n.get('thumb_page_canvas',
-      {page: id}, 'Thumbnail of Page {{page}}'));
-
-    div.setAttribute('data-loaded', true);
-
-    ring.appendChild(canvas);
-
-    var ctx = canvas.getContext('2d');
-    ctx.save();
-    ctx.fillStyle = 'rgb(255, 255, 255)';
-    ctx.fillRect(0, 0, this.canvasWidth, this.canvasHeight);
-    ctx.restore();
-    return ctx;
-  };
-
-  this.drawingRequired = function thumbnailViewDrawingRequired() {
-    return !this.hasImage;
-  };
-
-  this.draw = function thumbnailViewDraw(callback) {
-    if (!this.pdfPage) {
-      var promise = PDFView.getPage(this.id);
-      promise.then(function(pdfPage) {
-        this.setPdfPage(pdfPage);
-        this.draw(callback);
-      }.bind(this));
-      return;
-    }
-
-    if (this.renderingState !== RenderingStates.INITIAL) {
-      console.error('Must be in new state before drawing');
-    }
-
-    this.renderingState = RenderingStates.RUNNING;
-    if (this.hasImage) {
-      callback();
-      return;
-    }
-
-    var self = this;
-    var ctx = this.getPageDrawContext();
-    var drawViewport = this.viewport.clone({ scale: this.scale });
-    var renderContext = {
-      canvasContext: ctx,
-      viewport: drawViewport,
-      continueCallback: function(cont) {
-        if (PDFView.highestPriorityPage !== 'thumbnail' + self.id) {
-          self.renderingState = RenderingStates.PAUSED;
-          self.resume = function() {
-            self.renderingState = RenderingStates.RUNNING;
-            cont();
-          };
-          return;
-        }
-        cont();
-      }
-    };
-    this.pdfPage.render(renderContext).then(
-      function pdfPageRenderCallback() {
-        self.renderingState = RenderingStates.FINISHED;
-        callback();
-      },
-      function pdfPageRenderError(error) {
-        self.renderingState = RenderingStates.FINISHED;
-        callback();
-      }
-    );
-    this.hasImage = true;
-  };
-
-  this.setImage = function thumbnailViewSetImage(img) {
-    if (this.hasImage || !img)
-      return;
-    this.renderingState = RenderingStates.FINISHED;
-    var ctx = this.getPageDrawContext();
-    ctx.drawImage(img, 0, 0, img.width, img.height,
-                  0, 0, ctx.canvas.width, ctx.canvas.height);
-
-    this.hasImage = true;
-  };
-};
-
+//#include thumbnail_view.js
 //#include text_layer_builder.js
 
 var DocumentOutlineView = function documentOutlineView(outline) {