Javascript
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This document provides an introduction to JavaScript, including: - JavaScript is a client-side scripting language that makes web pages dynamic and interactive. It is supported by all major browsers. - There are two types of scripting languages: client-side (like JavaScript) that execute in the browser, and server-side (like PHP) that execute on the server. - The document outlines how to start programming in JavaScript using <script> tags, and covers JavaScript syntax including variables, data types, control structures, functions, operators, and built-in methods like alert().
![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](https://image.slidesharecdn.com/javascript-140329030011-phpapp02/85/Javascript-17-320.jpg)
Javascript
- 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
- 13. Output C Int a=10,b=25; Printf(‚%d %d‛,a,b); JavaScript Var a=10; var b=25; Document.write(a,b);
- 14. Control Structures C Conditional Control Structures • If • If else • Switch Loops • For • While • Do while JavaScript ‚Exactly the same as on left side‛
- 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
- 18. Questions? ‚A good question deserve a good grade…‛
- 19. End of Day
- 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: [email protected]