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 = valueReturn Value: It returns a reference to the String.prototype object.
Example 1: This example adds a property salary to the all objects.
<!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.
<!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: