Slide môn học PHP session 3 form handling in PHP
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Form Handling in PHP
Session 2
Review - I
PHP is a general purpose scripting language used for
developing dynamic web pages
PHP is developed from C-modules
PHP has become a popular tool for e-commerce
PHP 4.0 includes supportive features for the following:
Security for user inputs
Web servers
New constructions for
HTTP sessions
languages
Output buffering
PHP / Session 3 / Slide 2 of 21
Review - II
PHP is used for generating the following:
Files in formats like PDF and HTML
Emails
Graphical images like GIF and PNG
PHP script has the following tags:
?>: End tag
HTTP protocol is divided into following three parts:
Request and response line
HTTP header
Body of the protocol
PHP / Session 3 / Slide 3 of 21
Review - III
header( ) function is used to generate the HTTP headers.
It sends the HTTP commands to the server through HTTP
protocols.
PHP uses tools for developing and designing web pages.
These tools are the program text editors.
Gedit is the most popular text editor used for programming
on Linux platform
PHP / Session 3 / Slide 4 of 21
Objectives
Use the GET Method
Use the POST Method
Retrieve data from forms using variables
Use hidden fields
PHP / Session 3 / Slide 5 of 21
Forms - I
Form provides medium of interface between the client
and server
PHP provides us with the powerful feature of handling
forms
PHP provides built-in support for collecting data from
a HTML form
PHP / Session 3 / Slide 6 of 21
Forms - II
On submission of the form, the information is sent
to the Web server, which in turn passes the
information to the PHP script engine
Script
engine
processes
the
information,
manipulates it, and sends the output back to the Web
browser
PHP / Session 3 / Slide 7 of 21
Forms - III
A form consists of the following attributes:
Action: Specifies the Uniform Resource Locator
(URL) that will process the form data and send the
feedback
Method: Specifies the method by which data is to be
sent to the URL
PHP / Session 3 / Slide 8 of 21
GET Method - I
Specifies the Web browser to send all the user
information as part of the URL
Question mark is added at the end of the URL, which
indicates the ending of the URL and the beginning of
the form information
Information on the form is transmitted in the structure
of name/value pairs to the URL
PHP / Session 3 / Slide 9 of 21
GET Method - II
Multiple name/value pairs can be sent to the URL by
separating each pair with the ampersand (&) sign
Name/value pairs are similar to variables
Once name/value are on the Web server for
processing, PHP make them available as variables
Name/value pairs sent to the URL is a query string
GET Method transmits only limited data
PHP / Session 3 / Slide 10 of 21
POST Method - I
Specifies the Web browser to send all the user
information through the body of the HTTP request
Transmits more information through the body of
the HTTP request, as there no physical limit on the
amount of information passed through the body of
the HTTP request
PHP / Session 3 / Slide 11 of 21
POST Method - II
Information sent by the POST method is not
encrypted. As a result, it is easily accessible
to a hacker.
In order to make the information to be
secure, it is necessary to establish a secure
server connection
PHP / Session 3 / Slide 12 of 21
Difference in GET and POST - I
GET method sends information through the URL
whereas the POST method sends information through
the body of the HTTP request
GET method is less secure as all the users are able to
view the transmitted information in the URL
GET method enables to transmit less amount of
information as compared to the POST
PHP / Session 3 / Slide 13 of 21
Difference in GET and POST - II
In the GET method, the pages loaded are carefully
book-marked, whereas in POST method the pages
loaded are not properly book-marked
GET method retrieves the information whereas the
POST method manipulates the information on the
Web server
PHP / Session 3 / Slide 14 of 21
Retrieving Data Using GET
Method
The syntax to retrieve the data if we have used the GET
method is:
$varname = $_GET[‘variable’];
Where,
varname - Specifies the name of the variable in
which the data is to be stored
_GET[‘variable’]- Specifies the name of the
input variable
PHP / Session 3 / Slide 15 of 21
Retrieving Data Using POST
Method
To retrieve the data if we have used the POST
method, the syntax is:
$varname=$_POST[‘variable’];
Where,
varname - Specifies the name of the variable in which
the data is to be stored
POST[‘variable’] - Specifies the name of the input
variable
PHP / Session 3 / Slide 16 of 21
Hidden Fields - I
Hidden form field enables to pass information to the
Web server
Hidden field is similar to the text field
The difference is that the user cannot view the hidden
field and its contents
To view whether the form contains the hidden field,
the user needs to view the HTML source code of the
form
PHP / Session 3 / Slide 17 of 21
Hidden Fields - II
The syntax to define the hidden filed is:
VALUE=”PHP MESSAGE”>
Where,
INPUT TYPE - Specifies that the field is hidden
NAME - Specifies the name of the hidden field
VALUE - Specifies the value as it appears on the form
PHP / Session 3 / Slide 18 of 21
Summary - I
Form provides a medium of interaction where users can
fill in data
PHP has a built-in support for collecting data from a
HTML form
Information from the form is automatically available to
the script engine
Script engine processes the information
Server recognizes the form as a collection of codes
PHP / Session 3 / Slide 19 of 21
Summary - II
Attributes of a form as are as follows:
Action
Method
In order to create a Form, we use the opening and
closing <FORM> tags
Elements placed between the<FORM> tags,
automatically becomes a part of the form
The GET method specifies the browser to send the
values the user placed on the form to the URL
PHP / Session 3 / Slide 20 of 21
Summary - III
POST method informs the browser to send the values
the user placed on the form to the PHP script engine in
the body of the HTTP request
Hidden form fields enables form developers to pass
information, from a form to a script, or from one form
to another, before being passed to a script
Hidden form fields are not visible to users
PHP / Session 3 / Slide 21 of 21
