Using input in php

PHP Form Handling

The PHP superglobals $_GET and $_POST are used to collect form-data.

PHP — A Simple HTML Form

The example below displays a simple HTML form with two input fields and a submit button:

Example

When the user fills out the form above and clicks the submit button, the form data is sent for processing to a PHP file named «welcome.php». The form data is sent with the HTTP POST method.

To display the submitted data you could simply echo all the variables. The «welcome.php» looks like this:

The output could be something like this:

The same result could also be achieved using the HTTP GET method:

Example

and «welcome_get.php» looks like this:

The code above is quite simple. However, the most important thing is missing. You need to validate form data to protect your script from malicious code.

Think SECURITY when processing PHP forms!

This page does not contain any form validation, it just shows how you can send and retrieve form data.

However, the next pages will show how to process PHP forms with security in mind! Proper validation of form data is important to protect your form from hackers and spammers!

GET vs. POST

Both GET and POST create an array (e.g. array( key1 => value1, key2 => value2, key3 => value3, . )). This array holds key/value pairs, where keys are the names of the form controls and values are the input data from the user.

Both GET and POST are treated as $_GET and $_POST. These are superglobals, which means that they are always accessible, regardless of scope — and you can access them from any function, class or file without having to do anything special.

$_GET is an array of variables passed to the current script via the URL parameters.

$_POST is an array of variables passed to the current script via the HTTP POST method.

When to use GET?

Information sent from a form with the GET method is visible to everyone (all variable names and values are displayed in the URL). GET also has limits on the amount of information to send. The limitation is about 2000 characters. However, because the variables are displayed in the URL, it is possible to bookmark the page. This can be useful in some cases.

GET may be used for sending non-sensitive data.

Note: GET should NEVER be used for sending passwords or other sensitive information!

When to use POST?

Information sent from a form with the POST method is invisible to others (all names/values are embedded within the body of the HTTP request) and has no limits on the amount of information to send.

Moreover POST supports advanced functionality such as support for multi-part binary input while uploading files to server.

However, because the variables are not displayed in the URL, it is not possible to bookmark the page.

Developers prefer POST for sending form data.

Next, lets see how we can process PHP forms the secure way!

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Dealing with Forms

One of the most powerful features of PHP is the way it handles HTML forms. The basic concept that is important to understand is that any form element will automatically be available to your PHP scripts. Please read the manual section on Variables from external sources for more information and examples on using forms with PHP. Here is an example HTML form:

Example #1 A simple HTML form

There is nothing special about this form. It is a straight HTML form with no special tags of any kind. When the user fills in this form and hits the submit button, the action.php page is called. In this file you would write something like this:

Example #2 Printing data from our form

A sample output of this script may be:

Hi Joe. You are 22 years old.

Apart from the htmlspecialchars() and (int) parts, it should be obvious what this does. htmlspecialchars() makes sure any characters that are special in html are properly encoded so people can’t inject HTML tags or Javascript into your page. For the age field, since we know it is a number, we can just convert it to an int which will automatically get rid of any stray characters. You can also have PHP do this for you automatically by using the filter extension. The $_POST[‘name’] and $_POST[‘age’] variables are automatically set for you by PHP. Earlier we used the $_SERVER superglobal; above we just introduced the $_POST superglobal which contains all POST data. Notice how the method of our form is POST. If we used the method GET then our form information would live in the $_GET superglobal instead. You may also use the $_REQUEST superglobal, if you do not care about the source of your request data. It contains the merged information of GET, POST and COOKIE data.

You can also deal with XForms input in PHP, although you will find yourself comfortable with the well supported HTML forms for quite some time. While working with XForms is not for beginners, you might be interested in them. We also have a short introduction to handling data received from XForms in our features section.

User Contributed Notes 3 notes

According to the HTTP specification, you should use the POST method when you’re using the form to change the state of something on the server end. For example, if a page has a form to allow users to add their own comments, like this page here, the form should use POST. If you click «Reload» or «Refresh» on a page that you reached through a POST, it’s almost always an error — you shouldn’t be posting the same comment twice — which is why these pages aren’t bookmarked or cached.

You should use the GET method when your form is, well, getting something off the server and not actually changing anything. For example, the form for a search engine should use GET, since searching a Web site should not be changing anything that the client might care about, and bookmarking or caching the results of a search-engine query is just as useful as bookmarking or caching a static HTML page.

Also, don’t ever use GET method in a form that capture passwords and other things that are meant to be hidden.

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5 Ways to Get Input Data in PHP: A Guide for Developers

Learn the most common ways to retrieve input data in PHP, including using $_POST, $_GET, readline(), and more. Improve your coding skills with our comprehensive guide.

• Using $_POST and $_GET to Retrieve Input Field Values
• Using readline() Function to Read Console or User Input
• Getting User Input
• Using $_REQUEST to Get Input Values into PHP Variables
• Using Value Attribute to Bind Value Inside the Input Field
• Using php://input to Read Raw POST Data of an HTML Form
• Other helpful code examples for retrieving input data in PHP
• Conclusion
• How to get input value in php?
• How to take input in php using form?
• How to get form data values in php?
• How to get input value in php without submit?

As a PHP developer, retrieving input data is a crucial part of your work. Input data refers to the information submitted by users through forms, URLs, or other means. This data is essential for creating dynamic web pages, validating user input, and providing personalized experiences. In this post, we will cover the most common ways to retrieve input data in PHP.

Using $_POST and $_GET to Retrieve Input Field Values

One of the most common ways to retrieve input data in PHP is by using the $_POST and $_GET superglobals. These superglobals are used to retrieve data that is submitted through HTML forms or query strings.

To retrieve input field values using $_POST or $_GET , you need to use the name attribute in HTML tags. The name attribute represents the key in the key-value pair, and the user’s input represents the value.

Here’s an example of how to retrieve input field values using $_POST :

Similarly, you can retrieve input field values using $_GET :

It’s important to note that $_POST is used to submit sensitive data like passwords, while $_GET is used to submit non-sensitive data like search queries. Using $_POST is more secure than using $_GET , as the data is not visible in the URL.

Using readline() Function to Read Console or User Input

Another way to retrieve input data in PHP is by using the readline() function. This function reads a line of input from the console or user.

Here’s an example of how to use the readline() function:

$input = readline("Enter your name: "); echo "Hello, $input!"; 

This code prompts the user to enter their name and then displays a personalized message.

The readline() function is useful when you want to retrieve input data from the command line interface or when building a CLI application.

Getting User Input

Using $_REQUEST to Get Input Values into PHP Variables

$_REQUEST is another superglobal used to retrieve input data in PHP. It is a combination of $_GET , $_POST , and $_COOKIE . This means that it can retrieve data from forms, URLs, and cookies.

Here’s an example of how to use $_REQUEST :

It’s important to note that using $_REQUEST can be risky as it can retrieve data from cookies, which can be manipulated by users.

Using Value Attribute to Bind Value Inside the Input Field

The value attribute is used to set a default value for an input field. This attribute can also be used to retain input data after a form submission.

Here’s an example of how to use the value attribute:

This code sets the default value of the input field to $username . If the user submits the form without changing the value, the value will be retained.

Using php://input to Read Raw POST Data of an HTML Form

The php://input stream allows you to read the raw data of an HTML form submission. This data is not processed by PHP and is sent as is.

Here’s an example of how to use php://input :

$data = file_get_contents('php://input'); 

It’s important to note that the data retrieved using php://input is not parsed and needs to be manually processed.

Other helpful code examples for retrieving input data in PHP

In Php , in particular, get input data in php code sample

Conclusion

Retrieving input data is a crucial part of PHP development. In this post, we covered the most common ways to retrieve input data in PHP. We discussed using $_POST and $_GET to retrieve input field values, the readline() function to read console or user input, $_REQUEST to retrieve input data from forms, URLs, and cookies, the value attribute to retain input data, and php://input to read raw POST data.

Remember to always validate user input and sanitize data to prevent security vulnerabilities. Happy coding!

Frequently Asked Questions — FAQs

What is input data in PHP, and why is it important to retrieve it?

Input data in PHP refers to the information that a user inputs into a form or console, which is then processed by the PHP script. Retrieving this data is crucial for performing operations on it, such as storing it in a database or displaying it to the user.

What are $_POST and $_GET, and how do they work to retrieve input field values?

$_POST and $_GET are superglobal variables in PHP that allow you to retrieve input field values from a form. $_POST is used to retrieve data submitted through the HTTP POST method, while $_GET is used for data submitted through the HTTP GET method.

What is the difference between using GET and POST methods to submit form data?

The main difference between using GET and POST methods to submit form data is that GET sends the data as part of the URL, while POST sends it as part of the HTTP request body. This means that POST is more secure for transmitting sensitive data, such as passwords.

How does the readline() function work to read input data in PHP?

The readline() function in PHP reads a line of input from the console or user and returns it as a string. It can be used to prompt the user for input or to read input from a file.

What is the value attribute in HTML tags, and how is it used to retain input data?

The value attribute in HTML tags is used to set the default value for an input field, which can be used to retain user input data. It is commonly used for form fields that need to be pre-filled with data, such as a user’s name or email address.

What is php://input, and how is it used to read raw POST data in PHP?

php://input is a stream in PHP that allows you to read raw POST data from an HTML form. It can be used to retrieve data in cases where the $_POST variable is not available or not working properly.

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