server side scripting

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28 Οκτ 2013 (πριν από 4 χρόνια και 10 μέρες)

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Contents

Client
-
data script


It refers to class of computer programs on the web that
are executed client
-
side, by the user`s web browser ,
instead of server side.


These are often embedded with in an HTML document
but they may also be contained in a separate file ,
which is referenced by the document that uses it.


Client
-
side scripts may also contain instructions for
the browser to follow if the user interacts within a
document in a certain way

JAVASCRIPT and WHAT
CAN IT DO


Most popular scripting language on the internet and works in
all major browsers such as internet explorer


Usually embedded directly into web pages


It is an interpreted language


It gives HTML designers a programming tool.


It can put dynamic text into an html page


It can react to events


It can read and write HTML elements


Can be used to validate data.


Can be used to create computer

Advantages of javascript


Speed :
-

being client side, javascript is very fast because
any code functions can be run immediately instead of
having to contact to the server and wait for an answer.


Simplicity :
-

javascript is relatively simple to learn and
implement.


Versatility :
-

javascript plays nicely with other
languages and be used in a huge variety of applications.


Server Load :
-

being client

side reduces the website
server.


Easy to debug and testing


No special editor is required for it.

Disadvantages of
Javascript


Security :
-

as the code executes the user`s
computer, in some cases it can be exploited for
malicious purpose.


Relying on End User :
-

Javscript is sometimes
interpreted differently by different browsers .
Where as server side script will always produce
the same output, client side scripts can be a little
predictable

How to add HTML tags
to the javascript


To insert a javascript into an HTML
page , we use the <script> tag


Inside the <script> tag we use the type
attribute to define the scripting
language.



EXAMPLE :
-


<html>


<body>


< script type=“text/JavaScript”>


document.write(“Hello World!”);


</script>


</body>


</html>


Javascript code and blocks


Javascript code is a sequence of Javascript statements.


Each statement is executed by the browser in the
sequence they are written


Javascript statements are grouped together in a block.


Block start with a left curly bracket and ends with a
right curly bracket.


The purpose of block is to make the sequence of
statement execute together.


JavaScript Comments


Single line comment start with //


Example //write a heading


Javascript multiple line comments start with /* and
end with*/.


Example /*the code will write one heading and two
pragraphs.*/

Javascript operators


Arithmetic operators


Assignment operators


Comparison operators


Logical operators


Conditional operator

Arithmetic operators : Y=5

OPERATOR

DESCRIPTION

EXAMPLE

RESULT

+


ADDITION

X=Y+2

X=7

_

SUBTRACTION

X=Y
-
2

X=3

*

MULTIPLICATION

X=Y*2

X=10

/

DIVISION

X=Y/2

X=2.5

%

MODULUS

X=Y%2

X=1

++

INCREMENT

X=++Y

X=6

_

DECREMENT

X=_Y

X=4

Assignment
operators:X
=10,Y=5

OPERATOR

EXAMPLE

SAME AS

RESULT

=

X=Y

X=5

+=

X+=Y

X=X+Y

X=15

-
=

X
-
=Y

X=X
-
Y

X=5

*=

X*=Y

X=X*Y

X=50

/=

X/=Y

X=X/Y

X=2

%=

X%=Y

X=X%Y

X=0

Comparison Operators : X=5

Logical
Operators:X
=6,Y=3

OPERATOR

DESCRIPTION

EXAMPLE

&&

AND

(X<10&&

Y > 1)
IS TRUE

||

OR

(X==5

|| Y==5)
IS FALSE)

!

NOT

!(X==Y)

IS
TRUE

Alert Box:


An alert box is often used if you want to make sure
information comes through to the user.


When an alert box pops up, the user will have to click
“OK” to proceed.


Syntax :


alert(“
sometext
”);

Confirm Box
:


A confirm box is often used if you want the user to
verify or accept something.


When a confirm box pops up, the user will have to
click either “OK” or “cancel’ to proceed.


If the user clicks “OK”, the box returns true. If the user
clicks “cancel”, the box returns false.


Syntax :


confirm(“
sometext
”);

Prompt Box:


A prompt box is often used if you want the user to
input a value before entering a page.


When a prompt box pops up, the user will have to click
either “OK’ or “cancel” to proceed after entering an
input value.


If the user clicks “OK” the box returns the input value.
If the user clicks “cancel” the box returns null.


Syntax:


prompt (
sometext
”, “
defaultvalue
”);

Javascript functions


A function contains a code that will be executed by an
event or by a call to the function.


We may call a function from anywhere with in a page


Functions can be defined both in the <head> and in
the <body> section of a document


Syntax :
-

Function
function

name(var1, var2…
varx
)

{

Some code

}

Example of function

The return statement


The return statement is used to specify the value that is returned from
thr

functions.


Therefore the functions that are going to return a value must use the return
statement.

Example



JavaScript events


Events are the beating heart of any JavaScript
application.


This gives us an overview of what event handling
is , what its problems are and how to write proper
cross
-
browser scripts


Without events there are no scripts.


Whenever a user of JavaScript takes action , he
causes an event.

Event Modeling


This is example of event modeling in which we
displays the date when a button is clicked.

<html>

<head>

<script type=“text/javascript”>

Function displayDate( )

{

Document.getElementBy(“demo”).innerHTML=date( );

</script>

</head>


<body>

<h1>My First Web Page</h1>

<p id=“demo”></p>

<button type=“button” onclick=“displayDate( )>Display
Date</button>

</body>

</html>

Document Object Model


The document object model is an application
programming interface(API) for valid HTML and well

formed XML documents.


It defines the logic structure of documents and the way
a document is accessed and manipulated.


With the Document Object Model , programmers can
build documents , navigate their structure and add,
modify , or delete elements and contents.



Ant thing found in an HTML or XML document can be
accessed , changed , deleted or added using the
Document Object Model, with few exceptions.


One important objective for the Document Object Model
is to provide a standard programming interface that can
be used in a wide variety of environments and
applications.


It is designed to be used with any programming
language .


The DOM is programming API for documents .

Example


We have a one HTML Table which is given below :
-

<TABLE>

<TBODY>

<TR>

<TD>
Shady Grove</TD>

</TR>

<TR>

<TD>Dorian</TD>

</TR>

</TBODY>

</TABLE>


<TABLE>

<TBODY>

<TR>

<TR>

<TD>

<TD>

<TD>

<TD>

SHADDY
GROVE

AEOLIAN

OVER THE
RIVER CHRLIE

DORIAN


Server


side scripting is a web server technology in
which a user `s request is fulfilled by running a script
directly on the web server to generate dynamic web
pages.


Server

side scripting is a option for delivering
customized HTML in contrast to client


side scripting,
where the HTML is modified typically by JavaScript in
the client `s machine after the HTML and java are sent
from the web server.


Server
-
side scripting is about “programming “ the
behavior of the browser.

Scripting Methods


Any scripting language can generate web pages through
CGI or an extension module or application server
framework.

1.
ASP :
-

active server pages (ASP) is Microsoft `s server
script engine for dynamically generated web pages.

2.
ASP.NET :
-

It is a set of web application development
technologies marketed by Microsoft.

3.
COLDFUSION :
-
Cross platform tag
-
based commercial
server side scripting system.

4.
ESP:
-

It is a server
-
side scripting language that is
designed to provide an easy interface to database
contents.


5.
JSP :
-

A Java


based system for embedding Java


related code in HTML pages.. JSP`s are compiled
into Java servlets by a JSP compiler.

6.
LASSO :
-

LASSO is a data source neutral interpreted
programming language and cross platform server.
LASSO is developed by Lassosoft, LLC.

7.
PHP:
-

PHP is a reflective programming language
originally designed to produce dynamic web pages.

8.
Server Side JavaScript :
-

it refers to Javascript that
returns on server

side.

9.
SMX:
-
SMX is a macro processing language shipped
with the Internet Factory`s Commerce Builder
software.




PHP started out as small open source project that
evolved as more people found out how useful it was.


PHP is a recursive acronym for “PHP: Hypertext
Preprocessor”.


PHP is a server side scripting language that is embedded
in HTML


It is used to manage dynamic content , databases ,
session tracking ,even build entire commerce site.


It is integrated with a number of popular databases ,
including My SQL , Oracle and Microsoft SQL server.


PHP supports a large number of major protocols such as
POP3 , IMAP and LDAP.


PHP4 added support for JAVA and disturbed object
architectures , making n
-
tier development a possibility
for the first time.


PHP is forgiving : PHP language tries to be as forgiving
as possible.


PHP syntax is like C Like

Uses of PHP


Performs system functions i.e from files on a system it
can create , open , read , write and close them.


Can handle forms , i.e gather data from files , save data
to file, through email you send data, return data to the
user.


Add , delete or modify elements within your database
through PHP


Access cookies variables and set cookies


We can restrict users to access some pages of any
website


It can encrypt data.

BASIC SYNTAX FOR PHP


The PHP parsing engine needs a way to differentiate
PHP code from other elements in the page. The
mechanism for doing so is known as `escaping to
PHP`. There are four ways to do this.


We have canonical PHP tags.


The most universally effective PHP tag style is


<?php….?>

Ways for sending
information.


There are two ways the browser can send information
to the web browser.


The GET Method


The POST Method

GET POST METHOD


Before the browser sends the information, it encodes it
using a scheme called URL encoding.


In this scheme , name/values pairs are joined with equal
signs and different pairs are separated by the
ampersand.




Spaces are removed and replaced wit the +character and
any other
nonalphanumeric

characters are

replaced
with a hexadecimal values.

The GET method


The get method sends the encoded user information
appended to the page request


The page and the encoded information are separated
by the ? character




The get method produces a long string that appears in
your server logs , in browser`s location :box.


The GET method is restricted to send
upto

1024
characters only


Never use GET method if you have password
or other sensitive information to be sent to
user.


It can`t be used to send binary data , like
images or word documents , to the server.


The data sent be GET method can be accessed
using QUERY_STRING environment variable.


The PHP provides $_GET associative array to
access all the sent information using the GET
method.

Example :
-

GET Method

<?php

If($_GET[“name”]||$_GET[“age”])

{

echo“welcome”.$_GET[`name`].“<br/>”;

echo “You are “.$_GET[`age`].“yearsold.”;

exit();

}

?>

<html>

<body>


<form action=“<?php$_PHP_SELF?>”method=“GET”>”

name:<input type=“text” name=“name”/>

Age:<input type=“text”name=“age”/>

<input type=“submit”/>

</form>

</body>

</html>



THE POST METHOD


The post method transfers information via HTTP
headers.


The information is encoded as describes in case of
GET method and put into a header called
QUERY_STRING.


This method does not have any restrictions on
dta

size
to be sent.


This method can be used to send ASCII as well as
binary data.


The data sent by POST method goes through HTTP
Header so security depends on HTTP protocol.


The PHP provides $_POST associative array to access all
the sent information using GET method.


EXAMPLE :
-

<?php

If($_POST[“name”]||$_POST[“age”])

{

echo“welcome”.$_POST[`name`].“<br/>”;

echo “You are “.$_POST[`age`].“yearsold.”;

exit();

}

?>

<html>


<body>

<form action=“<?php$_PHP_SELF?>”method=“POST”>”

name:<input type=“text” name=“name”/>

Age:<input type=“text”name=“age”/>

<input type=“submit”/>

</form>

</body>

</html>


PHP variables


All variables in PHP are denoted with a leading
dollar sign $.


The value of variable is the value of its most
recent assignment.


PHP does a good job of automatically converting
types from one to another when necessary .


Variables in PHP do not have intrinsic types
-
a
variable does not know in advance whether it will
be used to store a number or a string of
characters.

DATATYPES IN PHP


INTERGERS:
-

are whole numbers , without a decimal
point, like 574.


DOUBLES:
-
are floating point numbers , like 3.146.


BOOLEANS:
-
have only two possible values either true or
false.


NULL:
-
null is a special type that only has one value i.e.
null.


STRINGS:
-

are sequences of characters like “hello
friends”


Arrays :
-

arrays are names and indexed collection of
other values.


Resources :
-
are special variables that hold references to
resources external to PHP.


OBJECTS:
-

Objects are instances of programmer
-
defined
classes.

PHP CONTROL STRUCTURES


if…..else statement :
-

use this statement if you want to
execute some code if a condition is true and another
code if a condition is false .

if(condition)

Code to be executed if condition is true;

else

Code to be executed if condition is false;


Else if statement


If you want to execute some code if one of the several
conditions are true , use this statement.

if(condition)

Code to be executed if condition is true;

else if(condition)

Code to be executed if condition is true

Else

Code to be executed if condition is false;


The switch statement


If you want to select one of many blocks of code to be executed , use
the switch statement.

switch(expression)

{

case label 1

Code to be executed if expression=label 1;

break;

case label 2

Code o be executed if expression= label 2;

break;

default:

code to be executed

if expression is different from both label 1 and label 2;

}


THANK YOU



STUDENTS