diff --git a/README.rst b/README.rst
index 2681945..6dee908 100644
--- a/README.rst
+++ b/README.rst
@@ -26,7 +26,8 @@ Requirements
 
 Worth noting is that the browser requires a graphical environment to run. You
 already have this on your laptop, but on a server it will probably require
-deploying some additional infrastructure (typically X11). The vagrant
+deploying some additional infrastructure (typically X11; note that Xvfb does
+not support screenshots; Xvnc4, from package vnc4server, does). The vagrant
 configuration in the brozzler repository (still a work in progress) has an
 example setup.
 
@@ -181,7 +182,7 @@ Headless Chrome (experimental)
 
 `Headless Chromium <https://chromium.googlesource.com/chromium/src/+/master/headless/README.md>`_
 is now available in stable Chrome releases for 64-bit Linux and may be
-used to run the browser without a visibe window or X11 at all.
+used to run the browser without a visible window or X11 at all.
 
 To try this out, create a wrapper script like ~/bin/chrome-headless.sh:
 
diff --git a/brozzler/browser.py b/brozzler/browser.py
index dd9e1b9..09131f1 100644
--- a/brozzler/browser.py
+++ b/brozzler/browser.py
@@ -381,7 +381,7 @@ class Browser:
             on_request=None, on_response=None, on_screenshot=None,
             username=None, password=None, hashtags=None,
             skip_extract_outlinks=False, skip_visit_hashtags=False,
-            page_timeout=300):
+            page_timeout=300, behavior_timeout=900):
         '''
         Browses page in browser.
 
@@ -448,7 +448,7 @@ class Browser:
                     on_screenshot(jpeg_bytes)
                 behavior_script = brozzler.behavior_script(
                         page_url, behavior_parameters)
-                self.run_behavior(behavior_script, timeout=900)
+                self.run_behavior(behavior_script, timeout=behavior_timeout)
                 if skip_extract_outlinks:
                     outlinks = []
                 else:
diff --git a/brozzler/worker.py b/brozzler/worker.py
index a28f3fe..6253b63 100644
--- a/brozzler/worker.py
+++ b/brozzler/worker.py
@@ -105,7 +105,7 @@ class BrozzlerWorker:
             self, frontier, service_registry=None, max_browsers=1,
             chrome_exe="chromium-browser", warcprox_auto=False, proxy=None,
             skip_extract_outlinks=False, skip_visit_hashtags=False,
-            page_timeout=300):
+            page_timeout=300, behavior_timeout=900):
         self._frontier = frontier
         self._service_registry = service_registry
         self._max_browsers = max_browsers
@@ -117,6 +117,7 @@ class BrozzlerWorker:
         self._skip_extract_outlinks = skip_extract_outlinks
         self._skip_visit_hashtags = skip_visit_hashtags
         self._page_timeout = page_timeout
+        self._behavior_timeout = behavior_timeout
 
         self._browser_pool = brozzler.browser.BrowserPool(
                 max_browsers, chrome_exe=chrome_exe, ignore_cert_errors=True)
@@ -419,7 +420,8 @@ class BrozzlerWorker:
                 on_request=on_request, hashtags=page.hashtags,
                 skip_extract_outlinks=self._skip_extract_outlinks,
                 skip_visit_hashtags=self._skip_visit_hashtags,
-                page_timeout=self._page_timeout)
+                page_timeout=self._page_timeout,
+                behavior_timeout=self._behavior_timeout)
         if final_page_url != page.url:
             page.note_redirect(final_page_url)
         return outlinks