in Operator

  • Article

Tests for the existence of a property in an object.

result = property in object

Arguments

  • result
    Required. Any variable.
  • property
    Required. An expression that evaluates to a string expression.
  • object
    Required. Any object.

Remarks

The in operator checks if an object has a property named property. It also checks the object's prototype to see if the property is part of the prototype chain.

Requirements

Version 1

See Also

Operator Precedence | Operator Summary