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# Web Embedding
Unsurprisingly, one of WebAssembly's primary purposes is to run on the Web,
for example embedded in Web browsers (though this is
[not its only purpose](NonWeb.md)).
This means integrating with the Web ecosystem, leveraging Web APIs, supporting
the Web's security model, preserving the Web's portability, and designing in
room for evolutionary development. Many of these goals are clearly
reflected in WebAssembly's [high-level goals](HighLevelGoals.md). In
particular, WebAssembly MVP will be no looser from a security point of view
than if the module was JavaScript.
More concretely, the following is a list of points of contact between WebAssembly
and the rest of the Web platform that have been considered:
* WebAssembly's [modules](Modules.md) allow for natural [integration with
the ES6 module system](Modules.md#integration-with-es6-modules) and allow
synchronous calling to and from JavaScript.
* If allowed by the module, JavaScript can alias a loaded module's linear
memory via Typed Arrays. (To keep the Typed Arrays' lengths constant,
if linear memory is resized, any extant Typed Arrays are detached.)
* WebAssembly's security model should depend on [CORS][] and
[subresource integrity][] to enable distribution, especially through content
distribution networks and to implement
[dynamic linking](DynamicLinking.md).
* Once [threads are supported](PostMVP.md#threads), a WebAssembly module would
shared (including its heap) between workers via `postMessage()`.
- This also has the effect of explicitly sharing code so that engines don't
perform N fetches and compile N copies.
- WebAssembly may later standardize a more direct way to create a thread that
doesn't involve creating a new Worker.
* Once [SIMD is supported](PostMVP.md#fixed-width-simd) WebAssembly would:
- Be statically typed analogous to [SIMD.js-in-asm.js][];
- Reuse specification of operation semantics (with TC39);
- Reuse backend implementation (same IR nodes).
* Once [GC is supported](GC.md), WebAssembly code would be able to reference
and access and JS, DOM, and general WebIDL-defined objects.
[CORS]: https://www.w3.org/TR/cors/
[subresource integrity]: https://www.w3.org/TR/SRI/
[SIMD.js-in-asm.js]: http://discourse.specifiction.org/t/request-for-comments-simd-js-in-asm-js
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