JavaScript Boolean prototype Constructor
❮ JavaScript Boolean Reference
Example
Make a new method for JavaScript booleans:
 Boolean.prototype.myColor = function() {
  if (this.valueOf() == true) {
      return "green";
  } else {
    return = "red";
    }
};
Create a boolean, then call myColor():
var a = true;
 var b = a.myColor();
Try it Yourself »
Definition and Usage
The prototype constructor allows you to add new properties and methods to JavaScript booleans.
When constructing a property, ALL booleans will be given the property, and its value, as default.
When constructing a method, ALL booleans will have this method available.
Note: Boolean.prototype does not refer to a single boolean, but to the Boolean() object itself.
Note: Prototype is a global object constructor which is available for all JavaScript objects.
Browser Support
| Property | |||||
|---|---|---|---|---|---|
| prototype | Yes | Yes | Yes | Yes | Yes | 
Syntax
 Boolean.prototype.name = value
❮ JavaScript Boolean Reference

