Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
Answered on StackOverflow. The key is that there are many functions hidden from the documentation that need to be overridden, like evaluateToString().
Thank you very much! Now it is much more clear for me.
