CERTIFICATE IN JAVA SCRIPT

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CERTIFICATE IN JAVA SCRIPT -(C1099)

CERTIFICATE IN JAVA SCRIPT


JAVA SCRIPT

  • What is JavaScript?
  • History
  • Uses
  • Adding JavaScript to HTML
  • JavaScript syntax
  • JavaScript events
  • JavaScript classes
  • The HTML Document Object Model
  • What is JavaScript?

 

  • JavaScript is a programming language for use in
  • HTML pages

 

  • Invented in at Netscape Corporation
  • (LiveScript)

 

  • JavaScript has nothing to do with Java

 

  • JavaScript programs are run by an interpreter built
  • into the user's web browser (not on the server)
  • Where does JavaScript Fit In?

 

  • Recall
  • .
  • client opens connection to server
  • .
  • client sends request to server
  • .
  • server sends response to client
  • .
  • client and server close connection

 

  • What about Step ?
  • .
  • Client renders (displays) the response received from server

 

  • Step involves displaying HTML

 

  • And running any JavaScript code within the HTML
  • What can JavaScript Do?

 

  • JavaScript can dynamically modify an HTML page

 

  • JavaScript can react to user input

 

  • JavaScript can validate user input

 

  • JavaScript can be used to create cookies (yum!)

 

  • JavaScript is a full-featured programming language

 

  • JavaScript user interaction
  • does not require any
  • communication with the server
  • ros and Cons of JavaScript

 

  • Pros:

 

  • Allows more dynamic HTML pages, even complete web
  • applications

 

  • Cons:

 

  • Requires a JavaScript-enabled browser

 

  • Requires a client who trusts the server enough to run the
  • code the server provides

 

  • JavaScript has some protection in place but can
  • still cause security problems for clients

 

  • Remember JavaScript was invented in and web-
  • browsers have changed a lot since then
  • Using JavaScript in your HTML

 

  • JavaScript can be inserted into documents by
  • using the
  • SCRIPT
  • tag
  • Where to Put your Scripts

 

  • You can have any number of scripts

 

  • Scripts can be placed in the
  • HEAD
  • or in the
  • BODY

 

  • In the
  • HEAD
  • , scripts are run before the page is displayed

 

  • In the
  • BODY
  • , scripts are run as the page is displayed

 

  • In the
  • HEAD
  • is the right place to define functions
  • and variables that are used by scripts within the
  • BODY
  • External Scripts

 

  • Scripts can also be loaded from an external file

 

  • This is useful if you have a complicated script or
  • set of subroutines that are used in several different
  • documents
  • avaScript Variables

 

  • JavaScript has variables that you can declare with
  • the optional
  • var
  • keyword

 

  • Variables declared within a function are local to
  • that function

 

  • Variables declared outside of any function are
  • global variables
  • JavaScript Operators and Constructs

 

  • JavaScript has most of the operators we're used to
  • from C/Java
  • Simple User Interaction

 

  • There are three built-in methods of doing simple
  • user interaction

 

  • alert(msg)
  • alerts the user that something has happened

 

  • confirm(msg)
  • asks the user to confirm (or cancel)
  • something

 

  • prompt(msg, default)
  • asks the user to enter some text
  • avaScript Functions

 

  • JavaScript lets you define functions using the
  • function
  • keyword

 

  • Functions can return values using the
  • return
  • keyword
  • JavaScript Arrays

 

  • JavaScript has arrays that are indexed starting at 0

 

  • Special version of
  • for
  • works with arrays
  • Exception Handling

 

  • JavaScript also has try, catch, and throw keywords for handling JavaScript errors
  • Comments in JavaScript

 

  • Comments in JavaScript are delimited with // and /*
  • */ as in Java and C++
  • avaScript Objects

 

  • JavaScript is object-oriented and uses the same method-calling syntax as Java

 

  • We have already seen this with the document object

 

  • Built-In JavaScript Objects

 

  • Some basic objects are built-in to JavaScript

 

  • String Date Array Boolean Math
  • JavaScript Strings

 

  • A String object is created every time you use a
  • string literal (just like in Java)

 

  • Have many of the same methods as in Java

 

  • charAt, concat, indexOf, lastIndexOf, match, replace, search,
  • slice, split, substr, substring, toLowerCase, toUpperCase,
  • valueOf

 

  • There are also some HTML specific methods

 

  • big, blink, bold, fixed, fontcolor, fontsize, italics, link, small,
  • strike, sub, sup

 

  • Don't use the HTML methods (use CSS instead)

 

  • This is the worst kind of visual formatting

 

  • JavaScript Dates

 

  • The Date class makes working with dates easier

 

  • A new date is initialized with the current date

 

  • Dates can be compared and incremented
  • JavaScript Arrays and Booleans

 

  • We have already seen the Array class

 

  • The Boolean class encapsulates a boolean value

 

 


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