Quasis Demo — JavaScript Shell 1.4 Example:

This demos the EcmaScript Quasi Strawman. To get started, choose one of the canned examples from the drop-down at the top right.

Features: autocompletion of property names with Tab, multiline input with Shift+Enter, input history with (Ctrl+) Up/Down, Math, help
Values and functions: ans, print(string), props(object), blink(node), clear(), load(scriptURL), scope(object), debugDesugaring()
Quasi-handlers, raw`…`, safehtml`…`, msg`…`, html_msg`…`, re`…`