Memory64 (WebAssembly)Limited availability
Instructions accept 64-bit memory indexes.
Not yet supported in all major browsers — check the table and provide a fallback.
Browser support
DesktopChrome
1–132Not supported
133+Supportedsince Feb 4, 2025
Current: 155Edge
12–132Not supported
133+Supportedsince Feb 6, 2025
Current: 154Firefox
1–133Not supported
134+Supportedsince Jan 7, 2025
Current: 157Safari
✕Not supportedup to 27
Current: 27MobileChrome Android
18–132Not supported
133+Supportedsince Feb 4, 2025
Current: 155Firefox Android
4–133Not supported
134+Supportedsince Jan 7, 2025
Current: 157Safari iOS
✕Not supportedup to 27
Current: 27How to use
Not supported in Safari, Safari iOS. Use feature detection below and provide a fallback (or a polyfill) for those browsers.
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.