This is the source code of a script to be executed.
If VM mode is set, print the disassembly of bytecode before running if true.
This parameter is reserved for internal use and should be left as false
If the script has a return statement with an expression, this value will be the result of that expression otherwise it will be ScriptAny.UNDEFINED
This is the main entry point for evaluating a script program. If the useVM option was set in the constructor, bytecode compilation and execution will be used, otherwise tree walking.