zzencode - v3.0

Like jjencode, it encodes javascript into (almost) equivalent code written with only symbols.
This version has a little more randomness, and should be slightly shorter for longer codes.

"strict mode" uses an ES6 lambda expression to make the code runnable in strict mode.
"cleanup" deletes all variables after running, to prevent pollution of window namespace.
"with param" will add a param (shown at end of code) which could be referred to as this in pre-encoded code.

"values" field requires 4 different integers < 300, needs to run "calc vals" for these to function.
However, do not use "calc vals" when the debugger is open, or it will probably freeze your browser.