1.

Introduction to web application

Web application development is the creation of application programs that reside on remote

servers and are delivered to the user’s device over the Internet. A web application (web app)

does not need to be downloaded and is instead accessed through a network. An end user can

access a web application through a web browser such as Google Chrome, Safari, or Mozilla

Firefox. A majority of web applications can be written in JavaScript, Cascading Style Sheets

(CSS), and HTML5.

Web application development will typically have a short development life-cycle lead by a small

development team. Front-end development for web applications is accomplished through client-

side programming. Client refers to a computer application such as a web browser. Client-side

programming will typically utilize HTML, CSS and JavaScript. HTML programming will

instruct a browser how to display the on-screen content of web pages, while CSS keeps displayed

information in the correct format. JavaScript will run JavaScript code on a web page, making

some of the content interactive.

Server-side programming powers the client-side programming and is used to create

the scripts that web applications use. Scripts can be written in multiple scripting languages such

as Ruby, Java and Python. Server-side scripting will create a custom interface for the end-user

and will hide the source code that makes up the interface.

2. TCP/IP Application services

 Telnet

 File Transfer Protocol (FTP)

 Trivial File Transfer Protocol (TFTP)

  Simple Mail Transfer Protocol (SMTP)

 Network File System (NFS)

 Simple Network Management Protocol (SNMP)

 Domain Name System (DNS)

The Client/Server Model

TC/IP applications operate at the application or process layer of the

TCP/IP hierarchy as discussed in the preceding sections. TCP/IP protocol splits an application

into server and client components. The server component is a service provider that controls

commonly shared resources pertaining to a particular application on the network. The server

normally runs on a remote, high-powered, computer to which only authorized users have access.

The client component is the service user. That piece of software engages with the server in a

sequence of request-response data grams fulfilling certain user-specified demands or

requirements.
Telnet

Telnet is a program that allows a user with remote login capabilities to use the computing

resources and services available on the host. Telnet can also be used to connect other ports

serving user defined as well as well-known services.

A DOS user running Telnet, for example, can connect to a UNIX host or a mainframe computer.

The 90wn side of using Telnet, however, is that unless the user is familiar with the operating

system running on the remote platform, he or she cannot use the desired resources easily.

File Transfer Protocol (FTP)

File Transfer protocol is among the oldest protocols still used in the internet. ITP is widely

available on almost all-computing platforms, including DOS, OS/2, UNIX, and up to

the mainframe level. ITP is a file server access protocol that enables a user to transfer files

between two hosts across the network or Internet. This is also established through TCP.

Accessing ITP sites over the internet requires that the user must have the knowledge of the

location and the name of the desired files.

Trivial File Transfer Protocol (TFTP)

TITP, like ITP, is also an internet service intended for the transfer of files between hosts. Unlike

ITP, however, TITP does not rely on TCP for transport services. Instead, TITP uses UDP to

shuttle the requested file to the TITP client.

Simple Mail Transfer Protocol (SMTP)

The Simple Mail Transfer Protocol is an electronic mail (e-mail) service provider. It is intended

for the Transfer of e-mail messages across ·the network. SMTP uses TCP transport for the

reliable delivery of mail messages. When there is an outgoing mail, the SMTP client will connect

to the SMTP server and sends the mail to the remote server.

Network File System (NFS)

Network File System service enables hosts across the network to share file system resources

transparently among themselves. Although it all started on UNIX platforms, NFS can be

implemented on any platform, including DOS, NetWare, and Windows NT.

Simple Network Management Protocol (SNMP)

Using the Simple Network Management Protocol, LAN administrators can monitor and tune the

performance of TCP/IP (as well as non-TCP/IP) networks. Using SNMP, all kinds

of information about network performance can be gathered, including statistics, routing tables,

and configuration-related parameters. The information and configuration gathering capabilities

of SNMP make it an ideal tool for network troubleshooting and performance tuning.

Domain Name System (DNS)

Due to Internet explosion, it is not practical to keep an exhaustive hosts file for every host

because of the sheer volume of listing as well as addition, deletion and updating of new, old and

current hosts. Therefore, DNS is used to provide host-to-IP address mapping of remote hosts to

the local hosts and vice versa. As we know that each device connected directly to the network
must have an IP address that is uniquely assigned to it. The address takes the form of a dotted

decimal notation such as 128.45.6.89

3. Web Server

Web server is a computer where the web content is stored. Basically web server is used to host

the web sites but there exists other web servers also such as gaming, storage, FTP, email etc.

Web site is collection of web pages while web server is a software that respond to the request for

web resources.

Web Server Working

Web server respond to the client request in either of the following two ways:

Sending the file to the client associated with the requested URL.

Generating response by invoking a script and communicating with database

Basic operation

Apache HTTP Server

This is the most popular web server in the world developed by the Apache Software Foundation.

1 Apache web server is an open source software and can be installed on almost all operating

systems including Linux, UNIX, Windows, FreeBSD, Mac OS X and more. About 60% of the

web server machines run the Apache Web Server.

Internet Information Services (IIS)

The Internet Information Server (IIS) is a high performance Web Server from Microsoft. This

2. web server runs on Windows NT/2000 and 2003 platforms (and may be on upcoming new

Windows version also). IIS comes bundled with Windows NT/2000 and 2003; Because IIS is

tightly integrated with the operating system so it is relatively easy to administer it.

Lighttpd

The lighttpd, pronounced lighty is also a free web server that is distributed with the FreeBSD
3.
operating system. This open source web server is fast, secure and consumes much less CPU

power. Lighttpd can also run on Windows, Mac OS X, Linux and Solaris operating systems.

Sun Java System Web Server

This web server from Sun Microsystems is suited for medium and large web sites. Though the
4.
server is free it is not open source. It however, runs on Windows, Linux and UNIX platforms.

The Sun Java System web server supports various languages, scripts and technologies required
 for Web 2.0 such as JSP, Java Servlets, PHP, Perl, Python, and Ruby on Rails, ASP and

Coldfusion etc.

Jigsaw Server

Jigsaw (W3C's Server) comes from the World Wide Web Consortium. It is open source and free
5.
and can run on various platforms like Linux, UNIX, Windows, and Mac OS X Free BSD etc.

Jigsaw has been written in Java and can run CGI scripts and PHP programs.

Web Hosting

Web Hosting is a service that allows hosting/post-web-server applications (website or web page)

on a computer system through which web-browser clients can have easy access to electronic

content on the Internet.

Different types of Web hosting services are listed below:

 Free Hosting

 Virtual or Shared Hosting

 Dedicated Hosting

 Co-location Hosting

Free Hosting:

Advantages:

 Free of cost

 Use websites to place advertisements. banners and other forms of advertising media
  Disadvantages:

 Customer support is missing

 Low bandwidth and lesser data transfer

 No control over your website

Shared/Virtual Hosting:

Advantages:

 Easy and affordable

 Secured by hosting provider

 24/7 Technical support

Disadvantages:

 Shared resources can slow down the whole server

 Less flexible than dedicated hosting

Dedicated Hosting:

Advantages:

 Ideal for large business

 Strong database support

 Unlimited software support

 Powerful e-mail solutions

 Complete root access to your servers

Disadvantages:

 Its very expensive

 Requires superior skill sets

Co-located Hosting:

Advantages:

 Greater Bandwidth High Up-Time

 Unlimited Software Options

 High Security

Disadvantages:

 Difficult to configure and debug

 Its expensive

 Require high skills

4. Chunked Transfer

Chunks are requests to HTTP

 5. Caching Support

Caching web content helps improve upon the responsiveness of your websites by reducing the

load on backend resources and network congestion. Web caching is performed by retaining

HTTP responses and web resources in the cache for the purpose of fulfilling future requests from

cache rather than from the origin servers.

Web caching is the activity of storing data for reuse, such as a copy of a web page served by a

web server. It is cached or stored the first time a user visits the page and the next time a user

requests the same page, a cache will serve the copy, which helps keep the origin server from

getting overloaded.
 6. Extensibility

Extensibility allows you to customize an existing installation of an application at runtime without

recompiling or changing the original source code. Extensibility works in two areas of an

application: Extensibility in the UI helps to show more relevant and organized data to the end

user.

7. SGML

SGML stands for Standard generalized markup language is a Standard generalized markup

language that makes use of a superset of extensively used markup languages like HTML and

XML. It is used for marking up files and has the gain of now no longer depending on a particular

application.

Structure of SGML:

<mainObject>

<subObject>

</subObject>

</mainObject>

Syntax:

<NAME TYPE="user">

Geeks for Geeks

</NAME>
Code:

<EMAIL>

<SENDER>

<PERSON>

<FIRSTNAME>BSCS</FIRSTNAME>

</PERSON>

</SENDER>

<BODY>

<p>This is 6th Semester</p>

</BODY>

</EMAIL>

OUTPUT:

BSCS

This is 6th Semester

8. HTML5

HTML5 (Hypertext Markup Language 5) is a markup language used for structuring and

presenting content on the World Wide Web. It is the fifth and final major HTML version that is a

World Wide Web Consortium (W3C) recommendation. The current specification is known as

the HTML Living Standard.

  The DOCTYPE

DOCTYPEs in older versions of HTML were longer because the HTML language was SGML

based and therefore required a reference to a DTD.

HTML 5 authors would use simple syntax to specify DOCTYPE as follows −

<!DOCTYPE html>

 Character Encoding

HTML 5 authors can use simple syntax to specify Character Encoding as follows −

<meta charset = "UTF-8">

The <script> tag

It's common practice to add a type attribute with a value of "text/javascript" to script

elements as follows −

<script type = "text/javascript" src = "scriptfile.js"></script>

The <link> tag

So far you were writing <link> as follows −

<link rel = "stylesheet" type = "text/css" href = "stylefile.css">

Task

Visit different types of HTML tags and check how they work.
 9. Core XML:

 XML is a software- and hardware-independent tool for storing and transporting data.

 XML stands for extensible Markup Language

 XML is a markup language much like HTML

 XML was designed to store and transport data

 XML was designed to be self-descriptive

 XML is a W3C Recommendation

 It has sender information

 It has receiver information

 It has a heading

 It has a message body

All XML Elements Must Have a Closing Tag

In XML, it is illegal to omit the closing tag. All elements must have a closing tag:

<p>This is a paragraph.</p>

<br />

XML Tags are Case Sensitive

XML tags are case sensitive. The tag <Letter> is different from the tag <letter>.

Opening and closing tags must be written with the same case:

<message>This is correct</message>
XML Elements Must be Properly Nested

In HTML, you might see improperly nested elements:

<b><i>This text is bold and italic</b></i>

In XML, all elements must be properly nested within each other:

<b><i>This text is bold and italic</i></b>

XML Attribute Values Must Always be Quoted

XML elements can have attributes in name/value pairs just like in HTML.

In XML, the attribute values must always be quoted:

<note date="12/11/2007">

<to>Tove</to>

<from>Jani</from>

</note>

There are 5 pre-defined entity references in XML:

&lt; < less than

&gt; > greater than

 &amp; & ampersand

&apos; ' apostrophe

&quot; " quotation mark

10. XHTML

XHTML stands for EXtensible HyperText Markup Language. It is a cross between HTML and

XML language. XHTML is almost identical to HTML but it is stricter than HTML. XHTML is

HTML defined as an XML application. It is supported by all major browsers.

Code:

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE html

PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"

"DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">

<head>

<title>Strict DTD XHTML</title>

</head>
<body>

<div style="color:#090;font-size:40px;

font-weight:bold;text-align:center;

margin-bottom:-25px;">BSCS</div>

<p style="text-align:center;font-size:20px;">

6th Semester</p>

<p style="text-align:center;font-size:20px;">

Option to choose month:

<select name="month">

<option selected="selected">January</option>

<option>February</option>

<option>March</option>

<option>April</option>

<option>May</option>

<option>June</option>

<option>July</option>

<option>Augusy</option>

<option>September</option>
 <option>October</option>

<option>November</option>

<option>December</option>

</select>

</p>

</body>

</html>

Output:

11. XHTML MP

XHTML MP (eXtensible HyperText Markup Language Mobile Profile) is the markup language

defined in WAP 2.0. WAP 2.0 is the most recent mobile services specification created by the

WAP Forum. The specification of WAP CSS (WAP Cascading Style Sheet or WCSS) is also

defined in WAP 2.0. WAP CSS is the companion of XHTML Mobile Profile and they are used
together. With WAP CSS, you can easily change and format the presentation of XHTML MP

pages.

XHTML Mobile Profile is a subset of XHTML, which is the stricter version of HTML. XHTML

Mobile Profile is XHTML Basic (also a subset of XHTML) plus some additional elements and

attributes from the full version of XHTML.

The goal of XHTML Mobile Profile is to bring together the technologies for mobile Internet

browsing and that for the World Wide Web. Before the coming out of XHTML Mobile Profile,

WAP developers make use of WML and WMLScript to create WAP sites, while web developers

use HTML / XHTML and CSS style sheets to build web sites.

12. SOAP

Simple Object Access Protocol (SOAP) is a lightweight XML-based protocol that is used for the

exchange of information in decentralized, distributed application environments. You can transmit

SOAP messages in any way that the applications require, as long as both the client and the server

use the same method.

Message Format:

 SOAP message transmits some basic information as given below

 Information about message structure and instructions on processing it.

 Encoding instructions for application defined data types.

 Information about Remote Procedure Calls and their responses.

Format parts:

 Envelope:

It specifies that the XML message is a SOAP message. A SOAP message can be defined

as an XML document containing header and body encapsulated in the envelope. The fault

is within the body of the message.

 Header:

This part is not mandatory. But when it is present it can provide crucial information about

the applications.

 Body:

It contains the actual message that is being transmitted. Fault is contained within the body

tags.

 Fault:

This section contains the status of the application and also contains errors in the

application. This section is also optional. It should not appear more than once in a SOAP

message.

Advantages of SOAP

 SOAP is a light weight data interchange protocol because it is based on XML.

 SOAP was designed to be OS and Platform independent.

 It is built on top of HTTP which is installed in most systems.

 It is suggested by W3 consortium which is like a governing body for the Web.

 SOAP is mainly used for Web Services and Application Programming Interfaces (APIs).
 13. REST

REST stands for Representational State Transfer and API stands for Application Program

Interface. REST is a software architectural style that defines the set of rules to be used for

creating web services. Web services which follow the REST architectural style are known as

RESTful web services. It allows requesting systems to access and manipulate web resources by

using a uniform and predefined set of rules. Interaction in REST based systems happen through

Internet’s Hypertext Transfer Protocol (HTTP).

A Restful system consists of a:

 client who requests for the resources.

 server who has the resources.

 Uniform Interface

 Stateless

 Cacheable

 Client-Server

 Layered System

 Code on Demand

HTTP verbs: Some of the common HTTP methods/verbs are described below:

 GET

 POST

 PUT

 DELETE
 14. WML

WML stands for Wireless Markup Language (WML) which is based on HTML and HDML. It is

specified as an XML document type. It is a markup language used to develop websites for

mobile phones. While designing with WML, constraints of wireless devices such as small

display screens, limited memory, low bandwidth of transmission and small resources have to be

considered. WAP (Wireless Application Protocol) sites are different from normal HTML sites in

the fact that they are monochromatic (only black and white), concise and has very small screen

space, due to which content in the WAP sites will be only the significant matter, much like how

telegraph used to work in the olden days.

Features of WML:

 Text and Images

 User Interaction

 Navigation

 Context Management

Code:

<?xml version="1.0"?>

<!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.2//EN"

"-//WAPFORUM//DTD WML 1.1//EN" "http://www.wapforum.org/DTD/wml_1.1.xml">

<wml>
 <!-- This is first card-->

<card id="one" title="First Card">

<h1> BSCS </h1>

<p>

6th Semester

</p>

</card>

<!-- This is second card-->

<card id="two" title="Second Card">

<p>

This is created by WML

</p>

</card>

</wml>
Output:

15. XSL:

XSL (extensible Stylesheet Language) is a styling language for XML. XSLT stands for XSL

Transformations. This tutorial will teach you how to use XSLT to transform XML documents

into other formats (like transforming XML into HTML).

Code:

<?xml version="1.0" encoding="UTF-8"?>

<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">

<xsl:template match="/">

<html>

<body>

<h2>My CD Collection</h2>

<table border="1">

<tr bgcolor="#9acd32">

<th style="text-align:left">Title</th>

<th style="text-align:left">Artist</th>

</tr>

<xsl:for-each select="catalog/cd">

<tr>

<td><xsl:value-of select="title"/></td>

<td><xsl:value-of select="artist"/></td>

</tr>

</xsl:for-each>
 </table>

</body>

</html>

</xsl:template>

</xsl:stylesheet>

Output:
 16. Web Services:

Operations:

Web services are XML-based information exchange systems that use the Internet for direct

application-to-application interaction. These systems can include programs, objects, messages, or

documents. A web service is a collection of open protocols and standards used for exchanging

data between applications or systems.

Web services contain multiple service operations, which are stateless synchronous inbound

operations. The service operations are assigned to service interfaces which specify how to

perform service requests and serve as collectors for specific operation types.

The interaction involves the three operations: publish, find, and bind. These operations and roles

act upon the web services artifacts. The web service artifacts are the web service software

module and its description. The service provider hosts a network-associable module (web

service). Operations services handle the transfer of all or part of the day-to-day system
management responsibility for a customer's IT infrastructure (host/data center, client/desktop or

connectivity/network) and, in some cases, the transfer of ownership of the technology or

personnel assets to an outside vendor.

Processing Http Request

The ICM processes HTTP requests and responses. On the basis of the URL and the port, a

“local” handler in the ICM is addressed. Sharing out the requests among different handlers

increases performance because a user context does not have to be created for each request.

Step 1: Direct browser to URL

Step 2: Browser looks up IP

Step 3: Browser sends HTTP request

Step 4: Host sends back HTTP response

Step 5: The browser renders the response

HTTP response:

An HTTP response is made by a server to a client. The aim of the response is to provide the

client with the resource it requested, or inform the client that the action it requested has been

carried out; or else to inform the client that an error occurred in processing its request.

There are three steps:

 Message Status-Line

 HTTP Version

 Status Code
Cookies Coordinator:

Cookies are small files which are stored on a user’s computer. They are used to hold a modest

amount of data specific to a particular client and website and can be accessed either by the web

server or by the client computer

When cookies were invented, they were basically little documents containing information about

you and your preferences. For instance, when you select your language in which you want to

view your website, the website would save the information in a document called a cookie on

your computer, and the next time when you visit the website, it would be able to read a cookie

saved earlier. That way the website could remember your language and let you view the website

in your preferred language without having to select the language again.

A cookie can contain any type of information such as the time when you visited the website, the

items that you added into your shopping basket, all the links you clicked in website, etc.,

Types of internet Cookies

 Session Cookies

 Persistent Cookies

 Third-party cookies
Privacy And P3p

The Platform for Privacy Preferences Project (P3P) is an emerging industry standard that enables

web sites to express their privacy practices in a standardized format that can be automatically

retrieved and interpreted by user agents.

P3P is a machine-readable language that helps to express a website's data management practices.

P3P manages information through privacy policies. When a website used P3P, they set up a set

of policies that allows them to state their intended uses of personal information that may be

gathered from their site visitors.

Complex Http Interactions

Another type of interaction is one where an element has some control on the interaction between

two others. We call “complex” these types of interactions, to distinguish them from the more

usual pairwise, element-to-element relations traditionally assumed.

Examples:

 expandable sections of content

 custom input elements

 hover or animations

 overlays or dialogs

 single page apps

Dynamic Content Delivery

Dynamic content is mostly powered by applications and scripts that run on the server hosting the

website. When a user makes a request, these applications work in tandem with the web server to

parse the request, generate content based on the request, and deliver the content to the user as

though it were static content.

Although the result is the same, requesting dynamic content is different from requesting static

content. You still need a URL with the asset you wish to access, but the server can interpret the

URL in a variety of ways. For example, consider a request for the image rainbow.jpg from the

website www.example.com: http://www.example.com/images/rainbow.jpg

You might expect there to be an images/ folder in the web directory containing a file named

rainbow.jpg. However, that might not be the case. After a web server receives a request, it passes
it on to a scripting language such as ASP.NET, Perl, or PHP. These languages can handle a

variety of functions from requesting files from a database to querying third party service

providers. Ultimately, the goal of each language is to build an HTML file that the web server can

deliver back to the user.

Once the resulting HTML file has been delivered to the web server, the server then forwards the

content to the user. The URL of the dynamic content might look something like

this: http://www.example.com/images/rainbow.jpg/ ?id=14

Benefits of Dynamic Content

 It is personalizable. Every single response can be crafted based on the user’s request or

previous visits to the site.

 It is extensible. The scripting languages that power dynamic content can tap into a

variety of external resources including the local file system, databases, or other servers.

 It is interactive. Dynamic websites are a two-way street: they provide content to users,

and they allow users to submit information back to the server.

 It is seamless. By combining server-side scripts with scripts that run in the browser,

websites can load dynamic content over an already-loaded web page without the user

being aware of it.

Server Configuration

The web server configuration file is installed as part of the web server. The Web Server Plug-ins

Configuration Tool must re-configure the configuration file for a supported web server.

Configuration consists of adding directives that identify file locations of two files: Binary web

server plug-in file.

Complete the following steps during the install process:

 Choose an apache version. We recommend the latest version listed.

 Select the database you wish to install. We recommend MySQL and selecting the latest

version.

 Click enter to use the default MySQL data directory

 Enter a MySQL root password

 Select a PHP version. We recommend selecting the latest version.

 Install any required PHP modules. php-imagick is a good option if you’re not sure what

you need.

 Select 1 to install PHPMyAdmin

 Press any key to begin the install process

Server Security

Web server security refers to the tools, technologies, and processes that enable information

security (IS) on a Web server. There are three main types of Web server security: physical,

network and host.

All network connections are protected by a firewall, a hardware or software component that

prevents unauthorized access to or from a network.

Web Server Security encompasses two major areas:

The security of the data on the web server

The security of the services running on the web server

The data on a web server is protected by operating system security and access controls. Firewalls

and anti-virus software protect the services running on a web server. The data on the server may

be the most valuable asset and hence is the target of the most attacks. Data protection is achieved

by encrypting the information on the disk and using intrusion detection software to detect and

respond to intrusion attempts.

When a user is surfing the internet, he’s not just interested in getting to his destination quickly.

He also wants to know that he can get there safely. This is why Web server security is so

important. Information technology (IT) professionals can use several methods to protect a Web

server from malicious attacks.

One of the most basic methods is to use a firewall, which is a program that checks all Internet

traffic coming into and going out of the Web server, blocking any traffic that seems suspicious or

otherwise dangerous.

Open Source Web Server Security Tools

 Snort

 Nmap

 OpenVAS

 Metasploit

 Sqlmap

17. Architecture of Web Browser.

The architecture of a web browser has certain components. They are Controller/Dispatcher,

Interpreter, and Client Programs. The control unit in a CPU is a controller that takes in the input,

interprets it, and then instructs the device to work in a certain way.
web Browser is an application software that allows us to view and explore information on the

web. User can request for any web page by just entering a URL into address bar.

Web browser can show text, audio, video, animation and more. It is the responsibility of a web

browser to interpret text and commands contained in the web page.

Controller works as a control unit in CPU. It takes input from the keyboard or mouse, interpret it

and make other services to work on the basis of input it receives.

Interpreter receives the information from the controller and execute the instruction line by line.

Some interpreter are mandatory while some are optional For example, HTML interpreter

program is mandatory and java interpreter is optional.

Client Program describes the specific protocol that will be used to access a particular service.

Following are the client programs that are commonly used:

 HTTP

 SMTP

 FTP

 NNTP

 POP
Some Popular Web Browsers

Here is a list of 7 popular web browsers:

 Google Chrome

 Mozilla Firefox

 Apple Safari:

 Microsoft Edge

 Opera

 Brave

 Tor Browser
 18. Active Browser Pages

An active web page is a page where the browser performs the logic instead of the server. So for

example when you've got a page where you're showing share prices, then you want it to update

e.g. every 5 seconds. A solution would be to use AJAX with JavaScript

JavaScript

JavaScript is the world's most popular programming language.

JavaScript is the programming language of the Web.

JavaScript is easy to learn.

JavaScript is one of the 3 languages all web developers must learn:

1. HTML to define the content of web pages

2. CSS to specify the layout of web pages

3. JavaScript to program the behavior of web pages

Javascript is everywhere, it comes installed on every modern web browser and so to learn

Javascript you really do not need any special environment setup. For example Chrome, Mozilla

Firefox , Safari and every browser you know as of today, supports Javascript.

Javascript helps you create really beautiful and crazy fast websites. You can develop your

website with a console like look and feel and give your users the best Graphical User

Experience.

JavaScript usage has now extended to mobile app development, desktop app development, and

game development. This opens many opportunities for you as Javascript Programmer.

Due to high demand, there is tons of job growth and high pay for those who know JavaScript.

You can navigate over to different job sites to see what having JavaScript skills looks like in the

job market.

Great thing about Javascript is that you will find tons of frameworks and Libraries already

developed which can be used directly in your software development to reduce your time to

market.

DHTML
DHTML is used to create interactive and animated web pages that are generated in real-time,

also known as dynamic web pages so that when such a page is accessed, the code within the page

is analyzed on the web server and the resulting HTML is sent to the client's web browser
DHTML is not a technology; rather, it is the combination of three different technologies, client-

side scripting (JavaScript or VBScript), cascading style sheets and document object model.

Key Features: Following are the some major key features of DHTML:

 Tags and their properties can be changed using DHTML.

 It is used for real-time positioning.

 Dynamic fonts can be generated using DHTML.

 It is also used for data binding.

 It makes a webpage dynamic and be used to create animations, games, applications along

with providing new ways of navigating through websites.

 The functionality of a webpage is enhanced due to the usage of low-bandwidth effect by

DHTML.

 DHTML also facilitates the use of methods, events, properties, and codes.

AJAX

JAX is a developer's dream, because you can:

  Update a web page without reloading the page

 Request data from a server - after the page has loaded

 Receive data from a server - after the page has loaded

 Send data to a server - in the background

 AJAX = Asynchronous JavaScript And XML.

 AJAX is not a programming language.

 AJAX just uses a combination of:

 A browser built-in XMLHttpRequest object (to request data from a web server)

 JavaScript and HTML DOM (to display or use the data)

AJAX Examples

 Create a simple XMLHttpRequest, and retrieve data from a TXT file.

 Request Header Information

 Request XML Files

  Retrieve Server Data with PHP and ASP

 Retrieve Database Information

AJAX Applications

 View an XML CD catalog

 Display XML data in an HTML table

 Show XML data inside an HTML

 Navigate through XML nodes

 A simple CD catalog application

JSON
 JSON stands for JavaScript Object Notation

 JSON is a text format for storing and transporting data

 JSON is "self-describing" and easy to understand

JSON Example

This example is a JSON string:

'{"name":"John", "age":30, "car":null}'

It defines an object with 3 properties:

name

age

car

Each property has a value.

If you parse the JSON string with a JavaScript program, you can access the data as an object:

let personName = obj.name;

let personAge = obj.age;

 JSON stands for JavaScript Object Notation

 JSON is a lightweight data-interchange format

 JSON is plain text written in JavaScript object notation

 JSON is used to send data between computers

 JSON is language independent *

You can receive pure text from a server and use it as a JavaScript object.

You can send a JavaScript object to a server in pure text format.

You can work with data as JavaScript objects, with no complicated parsing and translations.

Storing Data

When storing data, the data has to be a certain format, and regardless of where you choose to

store it, text is always one of the legal formats.

JSON makes it possible to store JavaScript objects as text.

19. Approaches To Web Application Development

Stage 1. Getting to know the client

Stage 2. Discovery and project research

Stage 3. Wireframes and prototypes

Stage 4. UI design

Stage 5. Back-end development

Stage 6. Front-end development

Stage 7. Quality assurance

Stage 8. Launch

Stage 9. Post-launch QA and maintenance

There are three main types of web development: front-end development, back-end

development, and full stack development

Three essential structures can be used to build a Web site: sequences, hierarchies, and webs.

There are three basic types of structures: shell structures, frame structures and solid structures.

But some structures are a combination. Most containers used to hold liquids or small solids are

shell structures.

20. Programming In Any Scripting Language

A scripting language is a programming language that employs a high-level construct to interpret

and execute one command at a time. In general, scripting languages are easier to learn and faster

to code in than more structured and compiled languages such as C and C++

Scripting languages are a specific kind of computer languages that you can use to give

instructions to other software, such as a web browser, server, or standalone application. Many of
today's most popular coding languages are scripting languages, such as JavaScript, PHP, Ruby,

and Python.

There are many scripting languages some of them are discussed below:

 Bash

 Node js

 Ruby

 Python

 Perl

Advantages of scripting languages:

 Easy learning

 Fast editing

 Interactivity

 Functionality

21. Search Technologies

Most Popular Search Engine Technologies in 2022

 Sphinx.

 ElasticSearch.

 Splunk.

 Solr.

 MarkLogic.

 Algolia.

 Microsoft Azure Cognitive Search.

  Arango, Virtuoso, OpenSearch.

Search Engine refers to a huge database of internet resources such as web pages, newsgroups,

programs, images etc. It helps to locate information on World Wide Web.

User can search for any information by passing query in form of keywords or phrase. It then

searches for relevant information in its database and return to the user.

Search Engine Components

Generally there are three basic components of a search engine as listed below:

 Web Crawler

 Database

 Search Interfaces

Search Engine Working

Web crawler, database and the search interface are the major component of a search engine that

actually makes search engine to work. Search engines make use of Boolean expression AND,

OR, NOT to restrict and widen the results of a search. Following are the steps that are performed

by the search engine:

The search engine looks for the keyword in the index for predefined database instead of going

directly to the web to search for the keyword.

It then uses software to search for the information in the database. This software component is

known as web crawler.

Once web crawler finds the pages, the search engine then shows the relevant web pages as a

result. These retrieved web pages generally include title of page, size of text portion, first several

sentences etc.

22. Search Engine Optimization

Search engine optimization (SEO) is the art and science of getting pages to rank higher in search

engines such as Google. Because search is one of the main ways in which people discover

content online, ranking higher in search engines can lead to an increase in traffic to a website.

SEO Strategy

Step #1: Create a List of Keywords.

Step #2: Analyze Google's First Page.

Step #3: Create Something Different or Better.

Step #4: Add a Hook.

Step #5: Optimize For On-Page SEO.

Step #6: Optimize For Search Intent.

Step #7: Focus on Content Design.

Step #8: Build Links to Your Page.

23. Xml Query Language

XML Query Language (XQuery) is a query and programming language for processing XML

documents and data. XML data and other databases that store data in a format analogous to

HTML can be processed with XQuery

XQuery is to XML what SQL is to databases.

XQuery is designed to query XML data.

XQuery is the language for querying XML data

XQuery for XML is like SQL for databases

XQuery is built on XPath expressions

XQuery is supported by all major databases

XQuery is a W3C Recommendation

XQuery can be used to:

Extract information to use in a Web Service

Generate summary reports

Transform XML data to XHTML

Search Web documents for relevant information

Functions

XQuery uses functions to extract data from XML documents.

The doc() function is used to open the "books.xml" file:

doc("books.xml")

Path Expressions

XQuery uses path expressions to navigate through elements in an XML document.

The following path expression is used to select all the title elements in the "books.xml" file:

doc("books.xml")/bookstore/book/title

24. Semantic Web

Semantic Technology defines and links data on the Web (or within an enterprise) by developing

languages to express rich, self-describing interrelations of data in a form that machines can

process.

The Semantics of Programming Languages. Semantics, roughly, are meanings given for groups

of symbols: ab+c, "ab"+"c", mult(5,4). For example, to express the syntax of adding 5 with 4, we

can say: Put a "+" sign in between the 5 and 4, yielding " 5 + 4 ". However, we must also define

the semantics of 5+4.

Some examples of semantic technologies include natural language processing (NLP), data

mining, artificial intelligence (AI), category tagging, and semantic search. You might think of

the goal of semantic technologies as separating signal from noise.

Semantics are often used in everyday social interactions to convey meaning beyond the literal

meaning of spoken words. For example, if someone asks, “How are you?” the response may be,

“I'm fine,” even if the person is not really feeling fine.

 25. Future Web Application Framework
Today, web development continues to evolve with the emergence of new technologies such as

JavaScript frameworks and APIs, enabling the creation of more powerful and dynamic web

applications. The growth of artificial intelligence and machine learning has led to the

development of chatbots and voice assistants.

React. React, also known as ReactJS, is a well-known front-end JavaScript library for developing

user interfaces and related components. ...

Angular. ...

Vue.js. ...

Svelte. ...

jQuery. ...
Backbone.js. ...

Ember.js. ...

Semantic-UI.

Web development is a highly lucrative and exciting career path to consider in 2023. With the

rapid expansion of technology and internet usage, the demand for skilled web developers is

expected to rise significantly.