JavaScript Boolean Reference

JavaScript Booleans

JavaScript booleans can have one of two values: true or false.

The Boolean() Function

You can use the Boolean() function to find out if an expression is true:


Boolean(10 > 9)       // returns true
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Or even easier:


(10 > 9)              // also returns true
10 > 9                // also returns true
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For a tutorial about booleans, read our JavaScript Boolean Tutorial.

Boolean Properties

Property 説明
constructor Returns the function that created JavaScript's Boolean prototype
prototype Allows you to add properties and methods to the Boolean prototype

Boolean Methods

Method 説明
toString() Converts a boolean value to a string, and returns the result
valueOf() Returns the primitive value of a boolean