Superglobal variables in PHP





How to use Superglobals Variables in PHP

 

What is Superglobal variables in PHP?

In PHP  superglobals are predefined variables. Superglobal can be used to make variables available in every page without declaring them global. They are project level variables, it means  scope of those variables throughout the entire web application. They can be accessed from any page within the web application. Superglobal variables prefixed with $_ and followed by  some name. The name is written in capital letters. It is a predefined name and cannot be changed.


  • $_SERVER
  • $_FILES
  • $_COOKIE
  • $_SESSION
  • $_GET
  • $_POST
  • $_REQUEST
  • $_ENV
  • $GLOBALS

In this article we are going to use 3 super global variables.

$_GET :  Allows 100 char length URLs. URL can be added to bookmarks.
$_POST:  Max limit 8 kb. can be changed.

  •      Post_max_size defined in php.ini.
  •      URL not possible for bookmark.
  •      URL cant be visible in the browser.

$_REQUEST: can read $_GET, $_POST, $_COOKIE values.

 

1. Using GET variable:

In the previous blog we just worked on a simple form which sends the get request. Here I will use the same example form and connect with a PHP file which will display Get data.

 

  1.  Create one project folder in Server
  2.  Create 2 files: 1.hello.html, 2. hello.php in the project.
  3.  Open hello.html and enter some name
  4.  Click Go button
  5.  PHP file will display the name that you entered in form

 

hello.html

<html>
 
<body>
 
<form name="sampleform" action="hello.php" method="get"> 
 
Enter Name:<input type="text" name="user">
 
<input type="submit" name="submit" value="Go" >
 
</form> 
  
</body>
 
</html>

 

coding-zon-hello-form

hello.php

 


<?php
	
echo "Hello ".$_GET["user"];

?>

 

 

coding-zon-hello-php

This image may explain you better. How Get request works.

When form submitted URL submits the PHP filename and form data to the server. Server will opens the PHP file, PHP file stores all the submitted data in $_GET. Using $_GET we can print form data.

So in the above example when user entered some name and clicked on Go button the URL sending the request as shown in the below


http://localhost/coding-zon/phpforms/hello.php?user=John&submit=Go

when request received, server immediately opens the hello.php. PHP file stores submitted data in a global array called $_GET variable. Next echo statement read the 'user' value from $_GET array as shown, $_GET['user'] and prints it, with greeting message  'Hello' as a response.

 

coding-zon-get-request

 

 

 

Next - Learn How to Create Login form

 

Comments

Post a Comment

Popular posts from this blog

Using javascript pass form variables to iframe src

Image
   Open PDF in Bootstrap Modal Window   This tutorial shows How to pass a JavaScript/jQuery variable to bootstrap modal view and sets it to iframe  src attribute. It passes value dynamically to src attribute of the iframe. When the user clicks a link, it opens the URL in a popup window. This  code shows the PDF in a Model without download option by hiding the toolbar.  To show PDF toolbar in modal, just add #toolbar=1   in the above script. index.php <!DOCTYPE html> <html lang= "en" > <head> <title>Bootstrap Model with PDF Example - coding-zon</title> <meta charset= "utf-8" > <meta name= "viewport" content= "width=device-width, initial-scale=1" > <link rel= "stylesheet" href= "https://cdn.jsdelivr.net/npm/bootstrap@4.6.2/dist/css/bootstrap.min.css" > <script src= "https://cdn.jsdelivr.net/npm/jquery@3.6.1/dist/jquery.slim.
Read more

Creating a new PDF by Merging PDF documents using TCPDF

Image
Merging two PDFs in PHP What is PDF? The Portable Document Format. PDF stands for "Portable Document Format". Essentially, the format is used when you need to save files that cannot be modified but still need to be easily shared and printed. PDF is one of the most commonly used file types around. PDFs generally contain shareable data, such as text or photo documents etc., and are accessible to anyone who has a computer or smartphone. Unlike a Word file, which requires Microsoft Word to view or edit, most browsers will open a PDF. How to merge PDFs? You can merge several documents into one. In PHP, you have a library called TCPDF which allows you to combine one or more PDF documents to one single document. In this article, we will create a new PDF by Merging PDF documents using TCPDF. Download the PDFMerger-tcpdf.zip here. Unzip it and copy it to the PHP server. Copy the PDF files into the same folder that you want to combine. Open the file: merge-pdf-example.php Provide
Read more

Import excel file into mysql in PHP

Image
  Upload Excel file and Import  it into MySQL in PHP  Create a table in some database with given code.   Download Library - extract it, rename the folder to library . Create index.php file with given code in a server. Create excelUpload.php with given code. Create db_config.php . Create one Excel file with some sample data as shown in the below image of Excel file. Create ' uploads ' folder in the same directory. Now start server, run the index.php. Upload a .xls file. If Everything is fine, Excel data inserted in the above created MySQL table - tbl_products . PHP Version:   5.5.11 Folder Structure      Query: CREATE TABLE IF NOT EXISTS `tbl_products` ( `id` int ( 11 ) NOT NULL AUTO_INCREMENT, `productname` varchar ( 100 ) DEFAULT NULL , `description` varchar ( 100 ) DEFAULT NULL , PRIMARY KEY (`id`) )     Top index.php <!DOCTYPE html> <html> <head> <title> coding-zon Demo - Upload Excel to MySQL in PHP </title> <lin
Read more