JavaScript String prototype Property

Last Updated : 23 Jul, 2024

The prototype property allows to add new properties and methods to the existing JavaScript object types. There are two examples to describe the JavaScript String prototype property.

Syntax:

object.prototype.name = value

Return Value: It returns a reference to the String.prototype object.

Example 1: This example adds a property salary to the all objects.

html

<!DOCTYPE HTML>
<html>

<head>
    <title>
        JavaScript String prototype Property
    </title>
</head>

<body style="text-align:center;">

    <h1>GeeksForGeeks</h1>
    
    <p id="GFG_UP"></p>

    <button onclick="GFG_Fun();">
        Click Here
    </button>
    
    <p id="GFG_DOWN"></p>
    
    <script>
        var up = document.getElementById('GFG_UP');
        var down = document.getElementById('GFG_DOWN');
        
        function person(name, age) {
            this.name = name;
            this.age = age;
        }
        var p1 = new person("p1", 24);
        up.innerHTML = "Click on the button to add "
                + "a new property to all objects of"
                + " a given type.< br > " 
                + JSON.stringify(p1);

        function GFG_Fun() {
            person.prototype.salary = 1000;
            down.innerHTML = p1.salary;
        }
    </script>
</body>

</html>

Output:

Example 2: This example adds a method info to the all objects.

html

<!DOCTYPE HTML>
<html>

<head>
    <title>
        JavaScript String prototype Property
    </title>
</head>

<body style="text-align:center;">

    <h1>GeeksForGeeks</h1>

    <p id="GFG_UP"></p>

    <button onclick="GFG_Fun();">
        Click Here
    </button>
    
    <p id="GFG_DOWN"></p>
    
    <script>
        var up = document.getElementById('GFG_UP');
        var down = document.getElementById('GFG_DOWN');
        function person(name, age) {
            this.name = name;
            this.age = age;
        }
        var p1 = new person("p1", 22);
        up.innerHTML = "Click on the button to add"
                + " a new property to all objects "
                + "of a given type.< br > " 
                + JSON.stringify(p1);

        function getData(name, age) {
            return "Information of person <br>Name - '" 
                        + name + "'<br>Age - " + age;
        }

        function GFG_Fun() {
            person.prototype.info 
                    = getData(p1.name, p1.age);
                    
            down.innerHTML = p1.info;
        }
    </script>
</body>

</html>

Output:

How to Update Node.js and NPM to the Latest Version (2025)

PranchalKatiyar

Improve

Article Tags :

JavaScript String prototype Property

Similar Reads

Thank You!

What kind of Experience do you want to share?