- Prohibit eval() usage, same as Function or new  Function
  eval() requires run time compilation because the source text might not
  appear in the program or can be generated at run time. Run time compilation
  is required to support the Function constructor and the Function function
  when the body is not a string literal.
- Limit Unicode support
- Cut Number from 64bit to 32bit/16/8bit
- Limit recursion level
- Do not allow addition, deletion or assignment to the properties of built-in
  objects.
  This limitation is needed to support a more efficient implementation based
  on static compilation of built-in objects without risking that the objects
  are mutated on shadowed by dynamically added properties.
- Do not allow usage of with statement
  The with makes access to named references inefficient, because the scopes
  for such access cannot be compiled until run time.