diff -r bafa63ac44a2 -r 7c10f6d5635c rt/vm/src/main/java/org/apidesign/vm4brwsr/ByteCodeToJavaScript.java
--- a/rt/vm/src/main/java/org/apidesign/vm4brwsr/ByteCodeToJavaScript.java	Wed May 07 10:01:54 2014 +0200
+++ b/rt/vm/src/main/java/org/apidesign/vm4brwsr/ByteCodeToJavaScript.java	Wed May 07 11:41:41 2014 +0200
@@ -19,6 +19,7 @@
 
 import java.io.IOException;
 import java.io.InputStream;
+import java.util.Locale;
 import static org.apidesign.vm4brwsr.ByteCodeParser.*;
 
 /** Translator of the code inside class files to JavaScript.
@@ -1533,7 +1534,18 @@
                 case '_': sb.append("_1"); break;
                 case ';': sb.append("_2"); break;
                 case '[': sb.append("_3"); break;
-                default: sb.append(ch); break;
+                default: 
+                    if (Character.isJavaIdentifierPart(ch)) {
+                        sb.append(ch);
+                    } else {
+                        sb.append("_0");
+                        String hex = Integer.toHexString(ch).toLowerCase(Locale.ENGLISH);
+                        for (int m = hex.length(); m < 4; m++) {
+                            sb.append("0");
+                        }
+                        sb.append(hex);
+                    }
+                break;
             }
         }
         return sb.toString();