2. Introduction to Scripting
• Scripting Languages are mainly used to build the programming environment in
HTML document .It Makes Web pages dynamic and interactive.
• There are 2 types of scripting languages
• Client side scripting languages
• Are scripts that execute on client side or the browser. Browser Includes
Scripting Interpreter
• Eg: VBScript, JavaScript, Jscript and ECMA Script
• Server side scripting languages
• Are scripts that execute on server side
• Eg: PHP,JSP, ASP .NET
3. Features of JavaScript
C-based language developed by Netscape
Mainly used for client side scripting because it is supported by all
the browsers.
Platform Independence
JavaScript is NOT supported by old browsers (IE 1.0). You can
enable or disable JS in new browsers
4. How to start programming in JavaScript
• All JavaScript Code must be in between the below tags
<script>
// JavaScript Code goes here
</script>
5. How to start programming in JavaScript
• JavaScript can be embedded to any HTML code in two ways
–Immediate scripting
–Deferred Scripting
6. Immediate Mode Scripting
• SCRIPT tag can be placed in HEAD or BODY tag
• Placing JavaScript in the HEAD tag ensures readability.
• Scripts gets executed as the page loads.
<body>
<h4> Immediate Demo</h4>
<script language="JavaScript">
document.write("<h5> Using JavaScript</h5>");
</script>
</body>
7. <script language="JavaScript">
/*calling function when user clicks on the button */
function msg(){
alert("Hi");
}
</script>
<form name="f1">
<input type="button" value=" ok " onClick="msg()">
</form>
Deferred Mode Scripting
–Script is executed based on some user action
8. JavaScript – lexical structure
• JavaScript is object based and action-oriented.
• JavaScript is case sensitive.
• A semicolon ends a JavaScript statement
9. Commenting
C
// comment single line
/* comment
multiple lines */
JavaScript
//comment single line
/* Comment
multiple Lines*/
10. Declaring a variable
C
//Declaring a variable
Int a=10;
Char c=‘a’;
Float f=1.12;
JavaScript
//No need of prior Declarations
Var a=10; //local
b=15; //global
11. Variables in Detail
• Must start with a letter or an underscore and can have digits.
• The Data type is automatically decided by the usage.
• Scope is by default global. If a variable is prefixed by the keyword ‚var‛
within a function then it is a local variable.
• The formal parameters are local to the function.
function demo()
{
var inum1 = 10; // Local to the function
inum2 = 20; // Global to the document.
}
demo(); // Invoking function
inum1 = inum1+1; // Error because inum1 is local variable
inum2 = inum2+1; // no Error
12. JavaScript – Implicit data types
• JavaScript recognizes the following implicit data types
– Number
– String
– Logical
– Object
– The special value null
• Type conversion
– JavaScript automatically converts between data types
str = ‚100‛, num1 = 10, num2 = 20
num3 = num1+ num2
strsum = str + num2
strsum = num2 + str
30
10020
20100
15. Functions
C
Int findSum(int a,int b)
{
Int c;
c=a+b;
Return c
}
findSum(10,15);
JavaScript
function findSum(a,b)
{
c=a+b;
Return c;
}
findSum(10,15);
16. Operators
C
Arithmetic Operators
+, ++, -, --, *, /, %
Relational Operators
==, !=, ===, !==, >, >=, < , <=
Logical Operators
&&, ||, !
Assignment Operators
=, +=, -=, *=, /=, %=
Strict equal (===)
Strict not equal (!==)
Returns true if the operands are not
equal and/or not of the same type.
JavaScript
‚Exactly the same as on left side‛
17. Dialog boxes (Window Object methods)
• Alert dialog box - alert(message)
– Takes in a string argument and displays an alert box.
• Prompt dialog box - prompt(message,[inputDefault])
– Displays a message and a data entry field
• Confirm dialog box - confirm(message )
– Serves as a technique for confirming user actions
20. Contact Us
Emarald Mall (Big Bazar Building)
Mavoor Road, Kozhikode,
Kerala, India.
Ph: + 91 – 495 40 25 550
NC Complex, Near Bus Stand
Mukkam, Kozhikode,
Kerala, India.
Ph: + 91 – 495 40 25 550
Start up Village
Eranakulam,
Kerala, India.
Email: info@baabtra.com
