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JS
JavaScript error

SyntaxError

The JavaScript strict mode-only exception "applying the 'delete' operator to an unqualified name is deprecated" occurs when variables are attempted to be deleted using the delete operator.

Reference entryJavaScriptFetched
This is a reference entry from MDN Web Docs. A full explanation with fixes has not been written yet.

The error messages

SyntaxError: Delete of an unqualified identifier in strict mode. (V8-based)
As listed by MDN Web Docs
SyntaxError: applying the 'delete' operator to an unqualified name is deprecated (Firefox)
As listed by MDN Web Docs
SyntaxError: Cannot delete unqualified property 'a' in strict mode. (Safari)
As listed by MDN Web Docs

Details

Category
SyntaxError in strict mode only
Severity
error
Runtime
both

Related errors

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Source: MDN Web Docs. Data fetched 2026-09-25T01:48:37.273Z.