Javascript Reference - JavaScript Boolean prototype Constructor

The prototype constructor can add new properties and methods to JavaScript booleans.

Browser Support


`prototype`	Yes	Yes	Yes	Yes	Yes

Syntax

Boolean.prototype.name = value;

Example

The following code shows how to add new method for JavaScript booleans type.


<!DOCTYPE html>
<html>
<body>
<button onclick="myFunction()">test</button>
<!--from   w  ww  .  j a  va 2  s . c  o  m-->
<p id="demo"></p>

<script>
Boolean.prototype.toColor = function() {
    if (this.valueOf() == true) {
        return "black";
    } else {
        return "red";
    }
}  

function myFunction() {
    var a = true;
    document.getElementById("demo").innerHTML = a.toColor();
}
</script>

</body>
</html>

The code above is rendered as follows: