Index: examples/fortune.scm
==================================================================
--- examples/fortune.scm
+++ examples/fortune.scm
@@ -22,19 +22,21 @@
 ;; SOFTWARE.
 ;;
 
 (import
   (chicken fixnum)
-  (chicken io)
   (only (chicken blob) string->blob)
   (only (chicken time) current-seconds)
+  (chicken io)
+  (only (chicken port) call-with-output-string)
   (only srfi-1 break!)
-  (only srfi-13 string-null? string-prefix? string-join)
   srfi-4
+  (only srfi-13 string-null? string-prefix? string-join)
   tweetnacl
   lmdb
-  webview)
+  webview
+  (only webview-content write-js))
 
 (define rng
   (open-random-stream
    (string->blob "Not a very random stream key ;-)")
    (do ([v (make-u8vector random-stream-noncebytes)]
@@ -89,66 +91,78 @@
                 #f db #:from key)))
            (and key
                 (retry (substring key 0 (fx- (string-length key) 1)))))))
    #:read-only))
 
-(define (render-fortune)
+(define (make-fortune)
   (cond
     [(get-fortune)
      => (cut list 'pre <>)]
     [else
      '(pre ([style "text-color: grey;"]) "(nothing found)")]))
 
-(define (inject-fortune view)
-  (webview-eval view "document.getElementById('save').style.setProperty('display','none')")
-  (webview-inject view "fortune" (render-fortune)))
+(define (inject-fortune! view)
+  (webview-style-set! view "#save" "display" "none")
+  (webview-html-set! view "#fortune" (make-fortune)))
+
+(define (inject-editor! view)
+  (webview-style-set! view "#save" "display" "inline")
+  (webview-html-set! view "#fortune"
+   '(textarea ([cols "72"] [rows "16"] [wrap "off"] [style "font-family: monospace;"]))))
 
-(define (inject-editor view)
-  (webview-eval view "document.getElementById('save').style.setProperty('display','inline')")
-  (webview-inject view "fortune"
-   '(textarea ([cols "72"] [rows "16"] [wrap "off"])
-      "")))
+(define (make-invocation name #!optional selector)
+  (call-with-output-string
+   (lambda (port)
+     (display "window.external.invoke(" port)
+     (write-js name port)
+     (when selector
+       (display "+document.querySelector(" port)
+       (write-js selector port)
+       (display ").value" port))
+     (display #\) port))))
 
-(define (render-app)
-  `(begin
-     (div ([class "toolbar"])
-       (button ([type "click"] [onclick "external.invoke('random')"])
-         "Random")
-       (button ([type "click"] [onclick "external.invoke('add-file')"])
-         "Add File…")
-       (button ([type "click"] [onclick "external.invoke('edit')"])
-         "New…")
-       (button ([type "click"] [id "save"] [onclick "external.invoke('save:' + document.getElementById('fortune').getElementsByTagName('textarea')[0].value)"] [style "display: none;"])
-         "Save"))
-     (div ([class "content"])
-       (code ([id "fortune"])
-         ,(render-fortune)))))
+(define (inject-app! view)
+  (webview-html-set! view "#app"
+   `(begin
+      (div ([class "toolbar"])
+        (button ([type "button"] [onclick ,(make-invocation "random")])
+          "Random")
+        (button ([type "button"] [onclick ,(make-invocation "add-file")])
+          "Add File…")
+        (button ([type "button"] [onclick ,(make-invocation "edit")])
+          "New…")
+        (button ([type "button"] [onclick ,(make-invocation "save:" "#fortune textarea")]
+                 [id "save"] [style "display: none;"])
+          "Save"))
+      (div ([class "content"])
+        (code ([id "fortune"])
+          ,(make-fortune))))))
 
-(define (inject-app view)
-  (webview-inject view "app" (render-app)))
+(define (on-add-file view)
+  (and-let* ([p (webview-dialog view "Add File" #:open)]
+             [n (add-fortunes-file! p)])
+    (webview-dialog
+     view "Add File" #:info
+     (string-append (number->string n) " fortunes added"))))
 
 (webview
  "Fortune"
  (lambda (view msg)
    (cond
      [(string=? "load" msg)
-      (inject-app view)]
+      (inject-app! view)]
      [(string=? "random" msg)
-      (inject-fortune view)]
+      (inject-fortune! view)]
      [(string=? "add-file" msg)
-      (and-let* ([p (webview-dialog view "Add File" #:open)]
-                 [n (add-fortunes-file! p)])
-        (webview-dialog
-         view "Add File" #:info
-         (string-append (number->string n) " fortunes added")))]
+      (on-add-file view)]
      [(string=? "edit" msg)
-      (inject-editor view)]
+      (inject-editor! view)]
      [(string-prefix? "save:" msg)
       (add-fortune! (substring msg 5))
-      (inject-fortune view)]
+      (inject-fortune! view)]
      [else
       (webview-log (string-append "Unknown Message: " msg))]))
  #:width 640 #:height 320)
 
 (close-database-environment)
 
 ;; vim: set ai et ts=4 sts=2 sw=2 ft=scheme: ;;

Index: main.scm
==================================================================
--- main.scm
+++ main.scm
@@ -123,21 +123,64 @@
              int "webview_eval"
              nonnull-webview nonnull-c-string)
             view script))
     (error 'webview-eval "JavaScript evaluation failed")))
 
-(define (webview-inject view id html)
+(define (webview-style-set! view selector property value #!optional [priority ""])
+  (webview-eval
+   view
+   (call-with-output-string
+    (lambda (port)
+      (display "Array.prototype.forEach.call(document.querySelectorAll(" port)
+      (write-js selector port)
+      (display "),function(it){it.style.setProperty(" port)
+      (write-js property port)
+      (display #\, port)
+      (write-js value port)
+      (display #\, port)
+      (write-js priority port)
+      (display ")})" port)))))
+
+(define (webview-style-delete! view selector property)
+  (webview-eval
+   view
+   (call-with-output-string
+    (lambda (port)
+      (display "Array.prototype.forEach.call(document.querySelectorAll(" port)
+      (write-js selector port)
+      (display "),function(it){it.style.removeProperty(" port)
+      (write-js property port)
+      (display ")})" port)))))
+
+(define (webview-html-set! view selector html #!optional [outer? #f])
+  (webview-eval
+   view
+   (call-with-output-string
+    (lambda (port)
+      (display "document.querySelector(" port)
+      (write-js selector port)
+      (display ")." port)
+      (display (if outer? "outer" "inner") port)
+      (display "HTML=" port)
+      (write-js
+       (call-with-output-string (cut write-html html <>))
+       port)))))
+
+(define (webview-html-delete! view selector #!optional [outer? #f])
   (webview-eval
    view
    (call-with-output-string
     (lambda (port)
-      (display "document.getElementById(" port)
-      (write-js id port)
-      (display ").innerHTML=" port)
-      (write-js
-       (call-with-output-string (cut write-html html <>))
-       port)))))
+      (display "(function(it){" port)
+      (display
+        (if outer?
+          "it.parentNode.removeChild(it)"
+          "while(it.firstChild){it.removeChild(it.firstChild)}")
+        port)
+      (display "})(document.querySelector(" port)
+      (write-js selector port)
+      (display "))" port)))))
 
 (define (webview-dialog view title type #!optional value)
   (let ([type
          (case type
            [(#:open #:open-directory)

Index: webview.scm
==================================================================
--- webview.scm
+++ webview.scm
@@ -32,18 +32,21 @@
     (prefix (only utf8 string-length string-ref display) utf8-)
     (only srfi-13 string-pad)
     utf8-srfi-14
     (prefix unicode-char-sets unicode-)
     srfi-69)
-  (include 
+  (include
     "content.scm"))
 
 (module webview
   (webview?
    webview webview-terminate!
    webview-title-set! webview-fullscreen-set!
-   webview-eval webview-inject webview-dialog webview-log)
+   webview-eval
+   webview-style-set! webview-style-delete!
+   webview-html-set! webview-html-delete!
+   webview-dialog webview-log)
   (import
     scheme
     (chicken base)
     (chicken condition)
     (chicken fixnum)

Index: webview.wiki
==================================================================
--- webview.wiki
+++ webview.wiki
@@ -74,19 +74,50 @@
 
 Asynchronously triggers evaluation of the given <tt>SCRIPT</tt> code in
 the context of the page displayed by the given <tt>WEBVIEW</tt>.
 
 <h3><tt><nowiki>
-  (webview-inject WEBVIEW ID HTML) ⇒ VOID
+  (webview-style-set! WEBVIEW SELECTOR PROPERTY VALUE [PRIORITY]) ⇒ VOID
+</nowiki></tt></h3>
+
+Asynchronously triggers a style modification of all DOM elements matching the
+given <tt>SELECTOR</tt> on the page displayed by the given <tt>WEBVIEW</tt>.
+The given style <tt>PROPERTY</tt> is set to the given <tt>VALUE</tt> for the
+selected elements, optionally specifying a <tt>PRIORITY</tt> other than the
+default.
+
+<h3><tt><nowiki>
+  (webview-style-set! WEBVIEW SELECTOR PROPERTY VALUE [PRIORITY]) ⇒ VOID
+</nowiki></tt></h3>
+
+Asynchronously triggers a style modification of all DOM elements matching the given
+<tt>SELECTOR</tt> on the page displayed by the given <tt>WEBVIEW</tt>. The
+given style <tt>PROPERTY</tt> is removed from the selected elements.
+
+<h3><tt><nowiki>
+  (webview-html-set! WEBVIEW SELECTOR HTML [OUTER?]) ⇒ VOID
 </nowiki></tt></h3>
 
-Asynchronously triggers replacement of the DOM element with the given
-<tt>ID</tt> on the page displayed by the given <tt>WEBVIEW</tt> with the
+Asynchronously triggers replacement of the first DOM element matching the given
+<tt>SELECTOR</tt> on the page displayed by the given <tt>WEBVIEW</tt> with the
 given <tt>HTML</tt> content.
 
 <tt>HTML</tt> content is specified in the form accepted by
 <tt>write-html</tt>.
+
+If <tt>OUTER?</tt> is <tt>#f</tt> or not given, only the <em>contents</em> of
+the specified element are replaced, otherwise the entire element is replaced.
+
+<h3><tt><nowiki>
+  (webview-html-delete! WEBVIEW SELECTOR [OUTER?]) ⇒ VOID
+</nowiki></tt></h3>
+
+Asynchronously triggers removal of the first DOM element matching the given
+<tt>SELECTOR</tt> from the page displayed by the given <tt>WEBVIEW</tt>.
+
+If <tt>OUTER?</tt> is <tt>#f</tt> or not given, only the <em>contents</em> of
+the specified element are removed, otherwise the entire element is deleted.
 
 <h2>Dialogs</h2>
 
 <h3><tt><nowiki>
   (webview-dialog WEBVIEW TITLE TYPE [VALUE]) ⇒ VALUE