let
- OTHERDeclares a variable with block level scope
IE
- 5.5 - 10: Not supported
- 11: Partial support
Edge
- 12 - 86: Supported
- 87: Supported
Firefox
- 2 - 43: Disabled by default
- 44 - 83: Supported
- 84: Supported
- 85 - 86: Supported
Chrome
- 4 - 18: Not supported
- 19 - 40: Disabled by default
- 41 - 48: Partial support
- 49 - 86: Supported
- 87: Supported
- 88 - 90: Supported
Safari
- 3.1 - 9.1: Not supported
- 10 - 10.1: Partial support
- 11 - 13.1: Supported
- 14: Supported
- TP: Supported
Opera
- 9 - 12.1: Not supported
- 15 - 27: Disabled by default
- 28 - 35: Partial support
- 36 - 71: Supported
- 72: Supported
iOS Safari
- 3.2 - 9.3: Not supported
- 10 - 10.3: Partial support
- 11 - 13.7: Supported
- 14: Supported
Opera Mini
- all: Not supported
Android Browser
- 2.1 - 4.4.4: Not supported
- 81: Supported
Opera Mobile
- 10 - 12.1: Not supported
- 59: Supported
Chrome for Android
- 87: Supported
Firefox for Android
- 83: Supported
UC Browser for Android
- 12.12: Supported
Samsung Internet
- 4: Partial support
- 5 - 12.0: Supported
- 13.0: Supported
QQ Browser
- 10.4: Supported
Baidu Browser
- 7.12: Partial support
KaiOS Browser
- 2.5: Supported