JavaScript
Object Methods
JavaScript
Methods
JavaScript
methods are the actions that can be performed on objects.
A JavaScript
method is a property containing a function definition.
Property Value
firstName John
lastName Doe
age 50
eyeColor blue
fullName function() {return this.firstName + "
" + this.lastName;}
Methods are
functions stored as object properties.
Accessing
Object Methods
You create
an object method with the following syntax:
methodName :
function() { code lines }
You access
an object method with the following syntax:
objectName.methodName()
You will
typically describe fullName() as a method of the person object, and fullName as
a property.
The fullName
property will execute (as a function) when it is invoked with ().
This example
accesses the fullName() method of a person object:
Example
name
= person.fullName();
»
If you
access the fullName property, without (), it will return the function
definition:
Example
name
= person.fullName;
»
Using
Built-In Methods
This example
uses the toUpperCase() method of the String object, to convert a text to
uppercase:
var
message = "Hello world!";
var
x = message.toUpperCase();
The value of
x, after execution of the code above will be:
HELLO WORLD!
Adding New
Methods
Adding
methods to an object is done inside the constructor function:
Example
function
person(firstName, lastName, age, eyeColor) {
this.firstName = firstName;
this.lastName = lastName;
this.age = age;
this.eyeColor = eyeColor;
this.changeName = function (name) {
this.lastName = name;
};
}
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