diff -r 9d011ab3c192 -r 805b62b77f91 rt/vm/src/main/java/org/apidesign/vm4brwsr/VM.java
--- a/rt/vm/src/main/java/org/apidesign/vm4brwsr/VM.java	Wed Sep 02 23:20:01 2015 +0200
+++ b/rt/vm/src/main/java/org/apidesign/vm4brwsr/VM.java	Sat Dec 26 08:51:01 2015 +0100
@@ -655,10 +655,12 @@
                 + "      console.log('Will not register: ' + extension);\n"
                 + "      return false;\n"
                 + "    }\n"
+                + "    var cs = document['currentScript'];\n"
+                + "    var prefix = cs ? cs['src']['replace'](/\\/[^\\/]*$/,'/') : '';\n"
                 + "    extensions.push(extension);\n"
                 + "    var cp = config['classpath'];\n"
                 + "    if (cp) for (var i = 0; i < cp.length; i++) {\n"
-                + "      loadExtension(cp[i]);\n"
+                + "      loadExtension(prefix + cp[i]);\n"
                 + "    }\n"
                 + "    return null;\n"
                 + "  };\n");