JavaScript Tutorial

JS HomeJS EditorsJS How toJS Basic ProgramJS ConsoleJS VariableJS constJS Data TypesJS StringJS Type CastingJS KeywordsJS OperatorsJS Use StrictJS Escape SequencesJS Comments

JS Control Statements

JS ifJS if elseJS else ifJS BreakJS ContinueJS Switch Case

JS Looping

JS Loop ForJS Loop For InJS Loop WhileJS Loop Do While

JS Array

JS ArrayJS Array One DimensionalJS Array Multi DimensionalJS Array Associative

JS Functions

JS FunctionJS Function SelfJS Function call()JS Function apply()JS Call By ValueJS Call By ReferenceJS Function Closures

JS Scope

JS Scope GlobalJS Scope LocalJS Let

JS File Handling

JS File Handling

JS Error Handling

JS try catchJS throwJS finally

JS Select Particulars

JS getElementByID()JS getElementsByClassName()JS getElementsByTagName()JS getElementsByName()JS querySelector()JS querySelectorAll()

JS Popup

JS alert()JS confirm()JS prompt()

JS Events

JS EventsJS Media EventsJS Mouse EventsJS Keyboard EventsJS Form EventsJS Drag EventsJS Clipboard EventsJS Print EventsJS Animation EventsJS Transition EventsJS Server-Sent EventsJS Touch EventsJS Object Events

JS Methods

JS Array MethodsJS String MethodsJS Math MethodsJS Number MethodsJS Date MethodsJS Element MethodsJS Window MethodsJS Node MethodsJS Document MethodsJS Console MethodsJS Timing MethodsJS Navigator MethodsJS Miscellaneous Methods

JS Properties

JS Array PropertiesJS String PropertiesJS Number PropertiesJS MouseEvent PropertiesJS KeyboardEvent PropertiesJS AnimationEvent PropertiesJS TransitionEvent PropertiesJS Element PropertiesJS Window PropertiesJS Node PropertiesJS Document PropertiesJS Navigator PropertiesJS HashChangeEvent PropertiesJS Miscellaneous Properties

JS Regular Expressions

JS Regexp

JS Cookies

JS Cookies

JS Interview Programs

JS Common ProgramsJS Array ProgramsJS Converter ProgramsJS Star Patterns ProgramJS Number Patterns ProgramJS Alphabet Patterns Program

JS Reference

LEARN JSONLEARN AJAXJS KeycodeMIME TypesASCII Table

JavaScript in Operator

Last Updated:

JavaScript in Operator

The in operator returns a Boolean value indicates whether the specified property is in the specified object or its prototype chain.

Note: If you set a property to undefined but do not delete it, the in operator returns true for that property.

Example

HTML Online Editor
<!DOCTYPE html> <html> <body> <p id="point"></p> <script> var x = document.getElementById("point"); var bike = {brand: "Honda", color: "red"}; if ("model" in bike === false) bike.model = "cb1000r"; x.innerHTML = "Model : "+bike.model; </script> </body> </html>

Syntax

property in object

Parameter Values

ValueTypeExplanation
property Required A string representing a property name or array index.
object Required An object to check if it contains the property with specified name.

Return Values

ValueExplanation
true If the specified property is in the specified object.
false If the specified property is not in the specified object.

Browser Support

Devicedesktopmobileserver
Browser / PLgoogle chromesafarifirefoxinternet Exploreredgeoperagoogle chromesafarifirefoxedgeoperaandroid webviewsamsung internetnodejs
inYesYesYesYesYesYesYesYesYesYesYesYesYesYes

Share this Page

Meet the Author