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Lessons JavaScript Objects and Classes Bookmark and Share
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Simply speaking an objejct is a collection of properties and functions. Objects are very useful to organise data or information.

JavaScript has a number of useful built-in objects for use in our programs for example Data, string, array, etc. Recall that in the previous lesson we worked with a number of array properties and functions. In JavaScript we have the liberty to create our own objects too.

How to create objects in JavaScript?
It is very simple. We create an object in JavaScript with the new operator followed by the object name and a pair of parenthesis. The following line of code creates a Date object:

var dt = new Date();

Accessing Object Properties
The syntax for accessing a property of an object is:

objectName.propertyName ;

The following code demonstrates the use of the length property of the string object:

var domain = "pickatutorial.com";
var len= domain.length;
// the variable len now has the value 17

Calling / Invoking Object Functions
Functions usually perform some action on the object properties. The syntax for invoking a function on some object is as under:

objectName.methodName();

The following code converts our text to lowercase:

var domain = "PICKATUTORIAL.COM";
var lower = domain.toLowerCase();
// the value of variable lower now equals pickatutorial.com

Important note about JavaScript Classes
If you have some prior programming experience of any object oriented programming language like c++, you may have an idea of classes. The concept of classes is very integral to the concept of objects in any object oriented programming langauge.

As of this writing JavaScript is not a FULL object oriented programming language and, therefore, we do not and cannot define classes in JavaScript. JavaScript is prototype based, not class based.


Next >>> Lesson No. 19: JavaScript Objects and Classes 2





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