Change error message

Author: ledsun

ext/js/lib/js/browser.rb

@@ -19,7 +19,7 @@ def require_relative(relative_feature)
         code = response.text().await.to_s
         eval_code(code, location)
       else
-        raise LoadError.new "cannot load such file -- #{relative_feature}"
+        raise LoadError.new "cannot load such url -- #{location.url}"
       end
     end