JavaScript - Data Types

It is not necessary to define the data type when initializing the variables in Javascript. It automatically gets the data type of the variable according to the value stored in the variable. That is calling Dynamic Type Variables. Therefore Same  variable can be used to store following kind of data in JavaScript
1. String
    A set of characters can be stored by putting between the Double Quotes or Single Quote
    Syntax:
    var <variable name> = '<Value>' OR
    var <variable name> = "<Value>"

    Ex:
    var student = "John"; // OR
    var student = 'John';   

    var Relationship= "John's car"; // Can put single Quotes within Double Quotes 
    var car = 'John has "Toyota" car'; // Can put Double Quotes within Single Quotes

2. Number
    Numbers in the can be written with or without decimal places.
    var no1 = 50;
    var no1 = 53.25;

Javascript - Comments

We are using comments to make Javascript more readable and comments are not executed by JavaScript. That can be used to explain the coding. In JavaScript, there are two types of comments can be used,
01. Single Line Comments
      Single Line Comments begins with 02 forward slashes and there is no ending, its 
      applicable to the whole line which it puts.
      Syntax:
      // <Comment>

      Ex:
      // This is a single line Comment
      var no = 0; // This is Number type variable

02. Multi Line Comments
      Multi Line Comments begins with a /* and ends with */. 
      Syntax:
      /* <Comment> */

      Ex:
      /* This is a Multi line Comment
          Purpose of this comment is explain 
          the code with more than one line */

Javascript - Variables

Javascript variables uses to contain information. 

Syntax: 
var <name> = <value>

Ex: 
var No1 = 5;
var No2 = 10;
var total = No1 + No2;

Javascript Variable names;
1. must begins with a letter
2. can begins with $ or _
3. are case sensitive

How to define a Javascript Variable

1. Method 01
    var carName = "Toyota"

2. Method 02
    var carName;
    carName = "Toyota";

Web Programing for Beginners

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Priyal

PHP - Print the Processed data

It is the way to see the processed php data by sending it to the browser as an out put. You can display the contents within the browser to see the users. There are several ways allows in php to send out put to the browser. I'm discussed here most important & common methods here.

• echo() statement
  This is the most common out put generation method in php. echo() statement accept multiple arguments.
  syntax:
  echo (string arg1[, string arg2, ...]);
  

PHP - Arrays

There are two types of array namely,

• Single Dimensional Array
• Multi Dimensional Array 

Arrays can store multiple information in a single variable. If you are using variables to store 4 values then you need to the followings.
  $bookName = "Sample Book";
  $bookAuthor = "Author\'s Name";
  $bookPublished = "April 02, 2013"; 
  $bookPublisher = "Sample Book Publisher";
But you can store above all values to a single array. 

• Single Dimensional Arrays
  Ex:
  $book = array(
       "Sample Book",
       "Author's Name",
       "April 02, 2013",
       "Sample Book Publisher"
       ) //use a book array to store above values
  echo "Book Name : " . $book[0]; // Print 1st element of the array
  

PHP - Numbers

There are two types of Numbers can be declared with php.

• Whole Numbers
  
  Integer data type uses to store positive or negative whole Numbers (without decimal points). It is not required to define integers because php is a loosely typed language. You are define a whole number without double quotes then it automatically evaluate as an integer value. But you can force the value store as integer by using casting. 
  Ex:
  1, -50
  $num = 50 // Numbers are define without double or single quotes
  $num = (int) 50 // This is a casting example. Here force to store the value as integer.
  $num = (int) "5years" // Taken the value as 5
  $num = (int) "age10" // Taken the value as 0 


• Real Numbers
  Double and Float data type uses to store positive or negative whole Numbers (with decimal points). 
  Ex:
  15.3325, -5.586240
  $num = 50.5589// Real Numbers are define without double or single quotes
  $num = (double) 50.569 // This is a casting example. Here force to store the value as real number.
  $num = (double) "5.85Km" // Taken the value as 5.85
  $num = (double) "age10.6" // Taken the value as 0
  $num = (float) "10.53yards" // Taken the value as10.53