String builtins (WebAssembly)Limited availability
The WebAssembly builtin string functions mirror a subset of the JavaScript String API and adapt it to be efficiently callable without JavaScript glue code.
Not yet supported in all major browsers — check the table and provide a fallback.
Browser support
DesktopChrome
1–129Not supported
130+Supportedsince Oct 15, 2024
Current: 155Edge
12–129Not supported
130+Supportedsince Oct 17, 2024
Current: 154Firefox
1–133Not supported
134+Supportedsince Jan 7, 2025
Current: 157Safari
✕Not supportedup to 27
Current: 27MobileChrome Android
18–129Not supported
130+Supportedsince Oct 15, 2024
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.
Sub-features
Support for each part of the feature (7). The overall table above shows when the whole feature works.
| Sub-feature | Chrome | Edge | Firefox | Safari | Chrome Android | Firefox Android | Safari iOS |
|---|---|---|---|---|---|---|---|
| webassembly.api.Module.Module.compile_options | 130 | 130 | 134 | ✕ | 130 | 134 | ✕ |
| webassembly.api.compileStreaming_static.compile_options | 130 | 130 | 134 | ✕ | 130 | 134 | ✕ |
| webassembly.api.compile_static.compile_options | 130 | 130 | 134 | ✕ | 130 | 134 | ✕ |
| webassembly.api.instantiateStreaming_static.compile_options | 130 | 130 | 134 | ✕ | 130 | 134 | ✕ |
| webassembly.api.instantiate_static.compile_options | 130 | 130 | 134 | ✕ | 130 | 134 | ✕ |
| webassembly.api.validate_static.compile_options | 130 | 130 | 134 | ✕ | 130 | 134 | ✕ |
| webassembly.jsStringBuiltins | 130 | 130 | 134 | 26.2 | 130 | 134 | 26.2 |