Improved support on Code 39 barcodes

example/static_images.html

@@ -43,7 +43,7 @@
         <ul class="thumbnails"></ul>
       </div>
       <div id="interactive" class="viewport"></div>
-        <div id="debug"></div>
+        <div id="debug" class="detection"></div>
     </section>
           <footer>
         <p>

example/static_images.js

@@ -17,7 +17,7 @@ $(function() {
         },
         config: {
             reader: "code_39",
-            length: 4
+            length: 10
         },
         attachListeners: function() {
             $(".controls").on("click", "button.next", function(e) {