JavaScript

1. Random Number Generation
Var randomValue = Math.random();

2. random()
 The Random Method returns number between 0 (inclusive) and 1 (exclusive).
 Math.random();
 There are no parameters for the method random().

3. Shifting and Scaling
 The range of values produced directly by a random is often different than what is needed
in a specific application.
 Eg:
 Dice
 Coin Tosing

4. Scaling and Shifiting
Math.floor( 1 + Math.random() * 6 )
 Here, Math.random is multiplied with 6, so that we get a range from 0.0 to 6.0
 This is called scaling.
 Adding 1(here) to the obtained value is called shifting.
 Math.floor() is used to determine the closest integer not greater than the argument value
 Eg: Math.floor(6.75) is 6 and Math.floor(1.89) is 1
 (Program 1)

5. Displaying Random Images
 Web content that varies randomly can add dynamic, interesting effects to a page.
 Alert()
 Prompt()
 Scripts are often used to respond to user initiated events.
Has Limited Features In receiving input from the
user

6. Events
 Click Event
 Occurs when the user clicks on the button.
This style of Programming is known as event-driven programming

7. Event-Driven Programming
User interacts with the web
page element
Script is notified of the event
Script processes the event

8. Event Handler
 The Function that’s called when an event occurs is known as the event
handler.
 When a GUI event occurs in a form, the browser calls the specified event-
handling function.
 Before any event can be processed, each element must know which event-
handling function will be called when a particular event occurs.

9. Time for some real Examples