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This article is about how js uses instanceof. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

Instanceof

Operator is used to test whether an object has a prototype property of a constructor in its prototype chain

Grammar

Object instanceof constructor (object to detect instanceof constructor)

But in browsers, our script may need to interact between multiple windows. Multiple windows mean multiple global environments, and different global environments have different global objects and thus different built-in type constructors. This may cause some problems.

[] instanceof window.frames [0] .Array / / false

Because Array.prototype! = = window.frames [0] .Array.prototype, you must use Array.isArray (myObj) or Object.prototype.toString.call (myObj) = = "[object Array]" to determine whether myObj is an array

The solution to the above two problems is Object.prototype.toString.

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