Appychip: javascript

Introduction

Many programming languages uses class based object oriented based paradigm, However, JavaScript uses prototype based paradigm. Let's get more deeper into that....

JavaScript was simply used as a scripting language which was mainly used by web-designers to do simple dynamic tricks on web pages. With time the JavaScript has evolve as one of the important full featured programming language to built rich Internet application rather than just doing simple tricks on the website.

                                    Object Oriented JavaScript
JavaScript uses class-less based object oriented paradigm which is also known as prototype based object oriented paradigm.
In prototype based object oriented paradigm, rather than defining set of class templates from which the objects are created, the objects are declared as they are needed.

                                                Advantage
One of the major advantage of prototype based OOP paradigm is that the objects can be modified at runtime. This means that the definition structure of the object is not strict as the classes are not defined.

                                                  Example
Let us see an example of object oriented paradigm, A function serves as an object prototype. To create an instance of this object new keyword is used.

1
2
3

function Car() { }
var myCar = new Car();
console.log(myCar);

Here the function Car() serves as an object and myCar is an instance of Car().
The output of the above code is object{}

To see a complete example of the same Following is the code :

<html>
<head>
    <title>Learning Dojo</title>
    <script src="dojoroot/dojo/dojo.js">
</script>

</head>
<body>
<h1>Learning Dojo</h1>
<div>Object oriented javascript</div>
<ul id="list">
    <li>It is class-less based object oriented paradigm</li>
    <li>Allow to modify object at runtime</li>
    <li>class template need not to be defined</li>
</ul>
<script>
    function Car() { } //Here Car function serves as an object
    var myCar = new Car(); // myCar is an instance of Car object
    alert(myCar); // This will show the output as object in the alert-box
    
</script>
</body>
</html>

After running the above code in the browser we get the following output:

Introduction to javascript : 1

Javascript is a very easy to learn language.

1. Printing text to console:
write the text in double quote which you want to print to console
ex. "This text will be printed on console";

2. Counting length of the string:
use length function to count the length of the string
ex. "sample".length;

3. Data types in javascript:
There are data types in many languages like numbers, string etc.
In JavaScript also there are data types like numbers and string.
The numbers written without double quotes are number ex. 43, 78.9.
The text written within double quotes are considered as string ex. "43", "javascript"

4. confirm function :
Confirm function is used to take response from the user for a particular action.
A confirm box appears on the screen with some display text, ok and cancel button.
ex. confirm("try again?");

5.Prompt function :
Prompt function provides interaction with user. It provides a input box to take input from the user.
ex. Prompt("What is your name?");

Appychip

Tuesday, 3 June 2014

Introduction to Object Oriented Javascript

Monday, 23 December 2013

Introduction to javascript