Bulk memory operations (WebAssembly)Baseline · Widely available
Bulk memory operations, such as copy and init, mirror the efficiency of native memcpy and memmove operations.
Supported in all major browsers for at least 30 months — safe to use without fallbacks. Baseline since Oct 25, 2021. Widely available since Apr 25, 2024.
Browser support
DesktopChrome
1–74Not supported
75+Supportedsince Jun 4, 2019
Current: 155Edge
12–18Not supported
79+Supportedsince Jan 15, 2020
Current: 154Firefox
1–77Not supported
78+Supportedsince Jun 30, 2020
Current: 157Safari
1–15Not supported
15.1+Supportedsince Oct 25, 2021
Current: 27MobileChrome Android
18–74Not supported
75+Supportedsince Jun 4, 2019
Current: 155Firefox Android
4–68Not supported
79+Supportedsince Jul 28, 2020
Current: 157Safari iOS
1–15Not supported
15.1+Supportedsince Oct 25, 2021
Current: 27How to use
This feature is Baseline widely available — use it freely, no fallback needed.
Example
Full syntax and examples are on MDN — see the links below.
Feature detection
There’s no simple runtime check for this feature; rely on the support table and test in your target browsers.