# ECMAScript® 2026 Language Specification
Introduction This Ecma Standard defines the ECMAScript 2026 Language. It is the seventeenth edition of the ECMAScript Language Specification. ECMAScript is based on several originating technologies, the most well-known being JavaScript (Netscape) and JScript (Microsoft). The language was invent

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# Annex D (informative) Host Layering Points

See 4.2 for the definition of host.

# D.1 Host Hooks

HostCallJobCallback(...)

HostEnqueueFinalizationRegistryCleanupJob(...)

HostEnqueueGenericJob(...)

HostEnqueuePromiseJob(...)

HostEnqueueTimeoutJob(...)

HostEnsureCanCompileStrings(...)

HostFinalizeImportMeta(...)

HostGetImportMetaProperties(...)

HostGrowSharedArrayBuffer(...)

HostHasSourceTextAvailable(...)

HostLoadImportedModule(...)

HostGetSupportedImportAttributes(...)

HostMakeJobCallback(...)

HostPromiseRejectionTracker(...)

HostResizeArrayBuffer(...)

InitializeHostDefinedRealm(...)

# D.2 Host-defined Fields

[[HostDefined]] on Realm Records: See Table 19.

[[HostDefined]] on Script Records: See Table 34.

[[HostDefined]] on Module Records: See Table 38.

[[HostDefined]] on JobCallback Records: See Table 23.

[[HostSynchronizesWith]] on Candidate Executions: See Table 96.

[[IsHTMLDDA]]: See B.3.6.

# D.3 Host-defined Objects

The global object: See clause 19.

# D.4 Running Jobs

Preparation steps before, and cleanup steps after, invocation of Job Abstract Closures. See 9.5.

# D.5 Internal Methods of Exotic Objects

Any of the essential internal methods in Table 4 for any exotic object not specified within this specification.

# D.6 Built-in Objects and Methods

Any built-in objects and methods not defined within this specification, except as restricted in 17.1.