diff --git a/arvo/eyre.hoon b/arvo/eyre.hoon
index a8aaf39e9..c3c756a27 100644
--- a/arvo/eyre.hoon
+++ b/arvo/eyre.hoon
@@ -197,15 +197,6 @@
   =+  cuh=(turn `(list ,@t)`cug |=(a=@t set-cookie/a))
   hit(q (weld cuh q.hit))
 ::
-++  inject                                            ::  inject dependency
-  |=  [dep=@uvH max=[[%html ~] [[%head ~] hed=marl] [[%body ~] tal=marl] ~]]
-  ^-  manx
-  =:  hed.max  :_(hed.max ;meta(charset "utf-8", urb_injected "");)
-      tal.max  (welp tal.max ;script(urb_injected ""):"{(trip etag:js)}" ~)
-    ==
-  ?~  dep  max
-  max(hed :_(hed.max ;script@"/~/on/{<dep>}.js"(urb_injected "");))
-::
 ++  add-json                                            ::  inject window.urb
   |=  [urb=json jaz=cord]  ^-  cord 
   =-  (cat 3 (crip -) jaz)
@@ -228,13 +219,14 @@
   [sas ~[content-type/(moon mit)] [~ (taco rez)]]
 ::
 ++  render-tang                                         ::  tanks to manx
-  |=  tan=tang
+  |=  [dep=@uvH tan=tang]
   ;html
     ;head
       ;link(rel "stylesheet", href "/lib/base.css");
       ;title: server error
     ==
     ;body:div#c.err:pre:code:"{(wush 80 tan)}"
+    ;script@"/~/on/{<dep>}.js";
   ==
 ::
 ++  favi                                                ::  XX favicon
@@ -390,23 +382,6 @@
         urb.wreq.abort() // trigger keep
       }
     }
-    urb.waspElem = function(ele){
-      url = ele.src || ele.href
-      if(!url || (new URL(url)).host != document.location.host)
-        return;
-      urb.waspUrl(url)
-    }
-    urb.waspUrl = function(url){
-      var xhr = new XMLHttpRequest()
-      xhr.open("HEAD", url)
-      xhr.send()
-      xhr.onload = urb.waspLoadedXHR
-    }
-    urb.waspLoadedXHR = function(){urb.wasp(urb.getXHRWasp(this))}
-    urb.getXHRWasp = function(xhr){
-      var dep = xhr.getResponseHeader("etag")
-      if(dep) return JSON.parse(dep.substr(2))
-    }
 
     '''
   ::
@@ -461,14 +436,6 @@
       function(){document.getElementById("c").innerHTML = "" }
     )}
     '''
-  ++  etag
-    '''
-    if(!window.urb) window.urb = {}
-    urb.waspAll = function(sel){
-      Array.prototype.map.call(document.querySelectorAll(sel), urb.waspElem)
-    }
-    if(urb.wasp){urb.waspAll('script'); urb.waspAll('link')}
-    '''
   --
 ++  xml
   |%
@@ -847,16 +814,7 @@
         ?.  ?=(%mime p.cay)
           =+  bek=-:(need (tome p.tee))
           =+  bik=?+(r.bek bek [%ud %0] bek(r da/now))
-          =-  (execute tee bik [%flag [p.sih `~] -])
-          =-  `silk`[%cast %mime `[p.cay -]]
-          ?.  ?=([%ud 0] r.bek)  q.cay
-          ?+  p.cay  q.cay          :: inject dependency long-poll
-            %urb  =<  (slam !>(.) q.cay)
-                  |=  urb=manx
-                  ~|  [%malformed-urb urb]
-                  ?>  ?=([[%html ~] [[%head ~] *] [[%body ~] *] ~] urb)
-                  (inject p.sih urb)
-          ==
+          (execute tee bik [%flag [p.sih `~] %cast %mime q.sih])
         ~|  q.q.cay
         =+  ((hard ,[mit=mite rez=octs]) q.q.cay)
         =+  dep=(crip "W/{(pojo %s (scot %uv p.sih))}")
@@ -920,7 +878,7 @@
     |=  [sas=@ud dep=@uvH mez=tang]
     ^+  +>
     :: (back ha/~ dep %tang !>(mez))  ::tang->urb chain may be source of failure
-    (give-html sas ~ (inject dep (render-tang mez)))
+    (give-html sas ~ (render-tang dep mez))
   ::
   ++  give-html
     |=  [sas=@ud cug=(list ,@t) max=manx]
diff --git a/arvo/ford.hoon b/arvo/ford.hoon
index 607c5c15b..1d99f5b7d 100644
--- a/arvo/ford.hoon
+++ b/arvo/ford.hoon
@@ -48,6 +48,7 @@
 ++  cafe                                                ::  live cache
   $:  p=(set calx)                                      ::  used
       q=(map ,* calx)                                   ::  cache
+      r=(map ,@uvH deps)                                ::  dependss
   ==                                                    ::
 ::                                                      ::
 ++  calm                                                ::  cache metadata
@@ -101,11 +102,6 @@
   ^-  cafe                                              ::
   a(q (~(put by q.a) [-.b q.b] b))                      ::
 ::                                                      ::
-++  chub                                                ::  cache merge
-  |=  [a=cafe b=cafe]                                   ::
-  ^-  cafe                                              ::
-  [(~(uni in p.a) p.b) (~(uni by q.a) q.b)]             ::
-::                                                      ::
 ++  faun  (flux |=(a=vase [%& %noun a]))                ::  vase to gage
 ++  feel  (flux |=(a=cage q.a))                         ::  cage to vase
 ++  furl                                                ::  unwrap gage to cage
@@ -316,6 +312,12 @@
         [%warp [our p.bem] q.bem [~ %sing ren r.bem (flop s.bem)]]
       ==
     ::
+    ++  clad                                            ::  hash dependencies
+      |*  hoc=(bolt)  ^+  [*@uvH hoc]
+      ?:  ?=(%1 -.q.hoc)  [*@uvH hoc]
+      =^  dep  r.p.hoc  (daze [p.q r.p]:hoc)
+      [dep hoc]
+    ::
     ++  clef                                            ::  cache a result
       |*  sem=*
       |*  [hoc=(bolt) fun=(burg)]
@@ -485,7 +487,7 @@
     ++  dash                                            ::  process cache
       |=  cof=cafe
       ^+  +>
-      %_(+> jav.bay q.cof)
+      %_(+> jav.bay q.cof, deh.bay r.cof)
     ::
     ++  diff                                            ::  diff
       |=  [cof=cafe kas=silk kos=silk]
@@ -532,29 +534,28 @@
       ==
     ::
     ++  daze                                            ::  remember depends
-      |=  dep=(set beam)
-      ^+  [*@uvH deh.bay]
+      |=  [dep=(set beam) deh=(map ,@uvH deps)]
+      ^+  [*@uvH deh]
       =.  dep
         =<  (sa (skip (~(tap in dep)) .))
         |=  dap=beam  ^-  ?
         ?~  s.dap  |
         =>(.(s.dap t.s.dap) |((~(has in dep) dap) $))
-      ?~  dep  [0v0 deh.bay]
+      ?~  dep  [0v0 deh]
       =+  hap=(sham dep)
-      ?:  (~(has by deh.bay) hap)
-        [hap deh.bay]
-      [hap (~(put by deh.bay) hap [%init dep])]
+      ?:  (~(has by deh) hap)
+        [hap deh]
+      [hap (~(put by deh) hap [%init dep])]
     ::
     ++  exec                                            ::  execute app
       ^+  ..zo
       ?:  !=(~ q.kig)  ..zo
-      =+  bot=(make [~ jav.bay] kas)
+      =+  bot=(make [~ jav.bay deh.bay] kas)
+      =^  dep  bot  (clad bot)
       =.  ..exec  (dash p.bot)
       ?-  -.q.bot
-        %0  =^  dep  deh.bay  (daze p.q.bot)
-            amok:(expo [%made dep q.q.bot])
-        %2  =^  dep  deh.bay  (daze p.q.bot)
-            amok:(expo [%made dep %| q.q.bot])
+        %0  amok:(expo [%made dep q.q.bot])
+        %2  amok:(expo [%made dep %| q.q.bot])
         %1  =+  zuk=(~(tap by p.q.bot) ~)
             =<  abet
             |-  ^+  ..exec
@@ -678,6 +679,7 @@
               (stag %ape ;~(pfix sig ape:read))
               (stag %arg ;~(pfix buc ape:read))
               (stag %alt ;~(pfix bar alt:read))
+              (stag %dep ;~(pfix hax day:read))
               (stag %dub ;~(pfix tis dub:read))
               (stag %fan ;~(pfix dot fan:read))
               (stag %for ;~(pfix com for:read))
@@ -1431,10 +1433,19 @@
           |=  cof=cafe  ^-  (bolt cage)
           ?~  p.hon  (flaw cof leaf/"ford: out of options" ~)
           (coop ^$(cof cof, hon i.p.hon) ..$(p.hon t.p.hon))
+        ::
+            %dep
+          =+  [dep bot]=(clad $(hon p.hon))    :: XX review
+          %+  cope  bot
+          %-  flux
+          |=  [mark vax=vase]
+          [%noun (slop [atom/'uvH' dep] vax)]
         ::
             %dub 
           %+  cope  $(hon q.hon)
-          (flux |=([mar=mark vax=vase] [mar [%face p.hon p.vax] q.vax]))
+          %-  flux
+          |=  [mar=mark vax=vase]
+          [mar [%face p.hon p.vax] q.vax]
         ::
             %fan
           %-  cope  :_  (flux |=(a=vase noun/a))
@@ -1675,7 +1686,7 @@
       ?>  (~(has by q.kig) tik)
       =+  `[ren=care bem=beam]`(~(got by q.kig) tik)
       ?~  rot
-        =^  dep  deh.bay  (daze ~)                      ::  dependencies?
+        =^  dep  deh.bay  (daze ~ deh.bay)              ::  dependencies?
         amok:(expo [%made dep %| (smyt ren (tope bem)) ~])
       =+  (cat 3 'c' ren)
       exec(q.kig (~(del by q.kig) tik), keg (~(put by keg) [- bem] r.u.rot))
diff --git a/arvo/zuse.hoon b/arvo/zuse.hoon
index c7352b158..8f3783afa 100644
--- a/arvo/zuse.hoon
+++ b/arvo/zuse.hoon
@@ -2493,6 +2493,7 @@
   $%  [%ape p=twig]                                     ::  /~  twig by hand
       [%arg p=twig]                                     ::  /$  argument
       [%alt p=(list horn)]                              ::  /|  options
+      [%dep p=horn]                                     ::  /#  insert dephash
       [%dub p=term q=horn]                              ::  /=  apply face
       [%fan p=(list horn)]                              ::  /.  list
       [%for p=(list (pair path:spur horn))]             ::  /,  switch by path
diff --git a/lib/urb-split.hoon b/lib/urb-split.hoon
new file mode 100644
index 000000000..86a13171b
--- /dev/null
+++ b/lib/urb-split.hoon
@@ -0,0 +1,9 @@
+::
+::::  /hoon/urb-split/lib
+  ::
+|=  [dep=@uvH urb=manx]  ^-  [hed=[@uvh marl] bod=[@uvH marl]]
+~|  [%malformed-urb urb]  :: XX types
+?>  ?=([[%html ~] [[%head ~] *] [[%body ~] *] ~] urb)
+=+  `[[%html ~] [[%head ~] hed=marl] [[%body ~] bod=marl] ~]`urb
+:-  [dep hed]                         :: Assume all dependencies are hard
+[0v0 bod]
diff --git a/mar/urb.hoon b/mar/urb.hoon
index 6fde8e3fb..786e81642 100644
--- a/mar/urb.hoon
+++ b/mar/urb.hoon
@@ -2,19 +2,42 @@
 ::::  /hoon/urb/mar
   ::
 /?  314
+/=  urb-wasp-data-js    /:    /%/wasp-data    /js/
 !:
-|_  own=manx
-::
+|_  [[dep=@uvH hed=marl] [dep-bod=@uvH bod=marl]]
+++  linked-deps-js
+  '''
+  urb.waspAll = function(sel){
+    [].map.call(document.querySelectorAll(sel), urb.waspElem)
+  }
+  if(urb.wasp){urb.waspAll('script'); urb.waspAll('link')}
+  '''
 ++  grow                                                ::  convert to
   |%
-  ++  html  (crip (poxo own))                           ::  convert to %html
   ++  mime  [/text/html (taco html)]                    ::  convert to %mime
+  ++  html  (crip (poxo hymn))                          ::  convert to %html
+  ++  hymn                                              ::  inject dependencies
+    ^-  manx
+    ;html
+      ;head
+        ;meta(charset "utf-8", urb_injected "");
+        ;*  ?~  dep  ~
+            :~  ;script@"/~/on/{<dep>}.js"(urb_injected "");  
+                ;script(urb_injected "")
+                  ;-  (trip urb-wasp-data-js)
+                  ;-  "urb.waspData({(pojo %s (scot %uv dep-bod))})"
+                ==
+            ==
+        ;*  hed
+      ==
+      ;body
+        ;*  bod
+        ;script(urb_injected ""):"{(trip linked-deps-js)}"
+      ==
+    ==
   --
 ++  grab  
   |%                                                    ::  convert from
-  ++  noun  manx                                        ::  clam from %noun
-  ::  conversion from hymn is handled specially by %eyre,
-  ::  which injects dependency information
-  ::  ++  hymn  !!                                      ::  inject into %hymn
+  ++  noun  ,[@uvH manx]                                ::  clam from %noun
   --
 --
diff --git a/mar/urb/wasp-data.js b/mar/urb/wasp-data.js
new file mode 100644
index 000000000..b50476fa6
--- /dev/null
+++ b/mar/urb/wasp-data.js
@@ -0,0 +1,30 @@
+urb.waspElem = function(ele){
+  url = ele.src || ele.href
+  if(!url || (new URL(url)).host != document.location.host)
+    return;
+  urb.waspUrl(url)
+}
+urb.waspUrl = function(url){
+  var xhr = new XMLHttpRequest()
+  xhr.open("HEAD", url)
+  xhr.send()
+  xhr.onload = urb.waspLoadedXHR
+}
+urb.waspLoadedXHR = function(){urb.wasp(urb.getXHRWasp(this))}
+urb.getXHRWasp = function(xhr){
+  var dep = xhr.getResponseHeader("etag")
+  if(dep) return JSON.parse(dep.substr(2))
+}
+
+urb.datadeps = {}
+urb.waspData = function(dep){
+  urb.datadeps[dep] = true
+  urb.wasp(dep)
+}
+urb.ondataupdate = urb.onupdate  // overridable
+
+var _onupdate = urb.onupdate
+urb.onupdate = function(dep){
+  if(urb.datadeps[dep]) urb.ondataupdate(dep)
+  else _onupdate(dep)
+}
diff --git a/ren/tree/body.hoon b/ren/tree/body.hoon
new file mode 100644
index 000000000..d138d6c1f
--- /dev/null
+++ b/ren/tree/body.hoon
@@ -0,0 +1,14 @@
+::
+::::  /hoon/body/tree/ren
+  ::
+/?    314
+/=    dat    /%  /tree-json/ :: default include
+^-  marl
+;=  ;script(type "text/javascript"): window.tree = {(pojo (joba %data dat))}
+    ;div.container
+      ;div.row#main
+        ;div#head;
+        ;div#body;
+      ==
+    ==
+==
diff --git a/ren/tree/hymn.hoon b/ren/tree/head.hoon
similarity index 87%
rename from ren/tree/hymn.hoon
rename to ren/tree/head.hoon
index c2ad5d73d..c235fca3b 100644
--- a/ren/tree/hymn.hoon
+++ b/ren/tree/head.hoon
@@ -1,10 +1,8 @@
 ::
-::::  /hoon/hymn/tree/ren
+::::  /hoon/head/tree/ren
   ::
 ::
 /?    314
-/-    tree-include
-/=    dat    /%  /tree-json/ :: default include
 /=    tub    /$  |=([bem=beam *] (flop s.bem))
 /=    aut
   /$  %+  cork  fuel                                    :: after parsing params,
@@ -15,9 +13,8 @@
 !:
 ::::
   ::
-;html
-  ;head
-    ;title: Tree
+^-  marl
+;=  ;title: Tree
     ;meta(name "viewport", content "width=device-width, initial-scale=1");
     ;link(type "text/css", rel "stylesheet", href "//cdnjs.cloudflare.com/ajax/libs/codemirror/4.3.0/codemirror.min.css");
     ;link(type "text/css", rel "stylesheet", href "/lib/css/fonts.css");
@@ -39,14 +36,4 @@
       "codemirror/4.3.0/mode/markdown/markdown.min.js");
     ;script(type "text/javascript", src "{?.(aut "" "/~~")}".
                                         "/~/at/lib/js/urb.js");
-  ==
-  ;body
-    ;script(type "text/javascript"): window.tree = {(pojo (joba %data dat))}
-    ;div.container
-      ;div.row#main
-        ;div#head;
-        ;div#body;
-      ==
-    ==
-  ==
 ==
diff --git a/ren/urb.hoon b/ren/urb.hoon
index 753aa8c2d..138e6c8b6 100644
--- a/ren/urb.hoon
+++ b/ren/urb.hoon
@@ -1,9 +1,11 @@
 ::
 ::::  /hoon/urb/ren
   ::
-/%    /,
-    /talk/log  /talklog-hymn/
-    /web/app   /|(/!hymn/ /tree-hymn/)
-    /      /tree-hymn/
+/+    urb-split    :: for single-page apps
+/%    /^  [hed=[@uvH marl] bod=[@uvH marl]]
+      /,      /web/app
+          /|(/;urb-split;/#/!hymn/ /urb-tree/)
+              /
+          /urb-tree/
       ==
-`manx`-.-
+-.-
diff --git a/ren/urb/tree.hoon b/ren/urb/tree.hoon
new file mode 100644
index 000000000..4f825f26c
--- /dev/null
+++ b/ren/urb/tree.hoon
@@ -0,0 +1,8 @@
+::  Combine /tree-head/ and /tree-body/
+::
+::::  /hoon/urb/ren
+  ::
+/=   hed    /#    /%   /:  /===/ren   /tree-head/  :: XX static
+/=   bod    /#    /%   /tree-body/
+^-  [hed=[@uvH marl] bod=[@uvH marl]]
+[hed bod]