web-feature: Let and const

Widely available

The let and const declarations define block-scoped variables.

WKWebView

macOS

*

iOS

*

Android WebView

Android

*

WebView2

Windows

*

WPE MiniBrowser

Linux

2026-08

Servo

Android

2026-08

ArkWeb

HarmonyOS

*

Chrome Browser

Android

49

Safari Browser

iOS

10