How to check if a checkbox is checked php?

Check whether a checkbox is checked with JavaScript.

Table of Contents Show

Check Whether a Checkbox is Checked
1. Read $_POST checked values
3. Table structure
4. Configuration
5. Insert and Display checked values from Database
6. Conclusion
How do I check if a checkbox is checked in PHP?
How can I check if a checkbox is checked?
How to check if checkbox is unchecked in PHP?
How to set checkbox to checked in PHP?

Display some text when the checkbox is checked:

Checkbox:

Checkbox is CHECKED!

Check Whether a Checkbox is Checked

Step 1) Add HTML:

Example

Checkbox:

Checkbox is CHECKED!

Step 2) Add JavaScript:

Example

function myFunction() {
// Get the checkbox
var checkBox = document.getElementById("myCheck");
// Get the output text
var text = document.getElementById("text");

// If the checkbox is checked, display the output text
if (checkBox.checked == true){
text.style.display = "block";
} else {
text.style.display = "none";
}
}

Try it Yourself »

In this tutorial, you can find comprehensive information on how to read whether a checkbox is checked in PHP.

Here, we will demonstrate two handy functions that will assist you in reading whether a checkbox is checked in PHP. Those functions are isset() and empty().

This is an inbuilt function that is capable of checking whether a variable is set.

With the isset() function, you can also check whether an array, a declared variable, or an array key is null. The isset() function returns false if it does and true in all the possible situations.

When you use it in your form and try to read all checked values as any other elements like – text box, text area, radio button, etc.

Get values of multiple checked chec...

Please enable JavaScript

Get values of multiple checked checkboxes and save to MySQL - PHP

echo $_POST['lang'];  // Checkbox element

you will get the last checked value.

You need to send the checkboxes value in the form of an Array when the form gets submitted then you can loop over $_POST values.

Demo Download

1. Read $_POST checked values

HTML

While creating multiple checkboxes add [] at the end of name attribute e.g. lang[]. Here, [] denotes an Array.

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

PHP

When the form is submitted then loop over

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

0 checkbox name using

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

if(isset($_POST['submit'])){

    if(!empty($_POST['lang'])) {    
        foreach($_POST['lang'] as $value){
            echo "value : ".$value.'<br/>';
        }
    }

}

Completed Code

<form method="post" action="">
    <span>Select languages</span><br/>
    <input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
    <input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
    <input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
    <input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

    <input type="submit" value="Submit" name="submit">
</form>

<?php
if(isset($_POST['submit'])){

    if(!empty($_POST['lang'])) {

        foreach($_POST['lang'] as $value){
            echo "value : ".$value.'<br/>';
        }

    }

}
?>

2. Demo

View Demo

3. Table structure

I am using

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

2 table in the example.

CREATE TABLE `languages` (
  `id` int(11) NOT NULL PRIMARY KEY AUTO_INCREMENT,
  `language` varchar(80) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

4. Configuration

Create a new

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

3 file.

Completed Code

<?php

$host = "localhost"; /* Host name */
$user = "root"; /* User */
$password = ""; /* Password */
$dbname = "tutorial"; /* Database name */

$con = mysqli_connect($host, $user, $password,$dbname);
// Check connection
if (!$con) {
  die("Connection failed: " . mysqli_connect_error());
}

5. Insert and Display checked values from Database

Create an Array

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

4 to store languages names.

Using this to create checkboxes by looping on it.

Insert –

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

5 submit convert

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

6 to string using

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

7. Check entry in

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

2 table if not exists then insert

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

9 in the table otherwise, update

if(isset($_POST['submit'])){

    if(!empty($_POST['lang'])) {    
        foreach($_POST['lang'] as $value){
            echo "value : ".$value.'<br/>';
        }
    }

}

0 value.

Display –

Fetch record from

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

2 table. If a record exists then explode

if(isset($_POST['submit'])){

    if(!empty($_POST['lang'])) {    
        foreach($_POST['lang'] as $value){
            echo "value : ".$value.'<br/>';
        }
    }

}

2 to get an Array and assign in

if(isset($_POST['submit'])){

    if(!empty($_POST['lang'])) {    
        foreach($_POST['lang'] as $value){
            echo "value : ".$value.'<br/>';
        }
    }

}

While looping on

<span>Select languages</span><br/>
<input type="checkbox" name='lang[]' value="PHP"> PHP <br/>
<input type="checkbox" name='lang[]' value="JavaScript"> JavaScript <br/>
<input type="checkbox" name='lang[]' value="jQuery"> jQuery <br/>
<input type="checkbox" name='lang[]' value="Angular JS"> Angular JS <br/>

4 Array check

if(isset($_POST['submit'])){

    if(!empty($_POST['lang'])) {    
        foreach($_POST['lang'] as $value){
            echo "value : ".$value.'<br/>';
        }
    }

}

5 value exists in

if(isset($_POST['submit'])){

    if(!empty($_POST['lang'])) {    
        foreach($_POST['lang'] as $value){
            echo "value : ".$value.'<br/>';
        }
    }

}

3 Array. If exists then assign

if(isset($_POST['submit'])){

    if(!empty($_POST['lang'])) {    
        foreach($_POST['lang'] as $value){
            echo "value : ".$value.'<br/>';
        }
    }

}

7 to

if(isset($_POST['submit'])){

    if(!empty($_POST['lang'])) {    
        foreach($_POST['lang'] as $value){
            echo "value : ".$value.'<br/>';
        }
    }

}

8 and use in the checkbox creation.

Completed Code

<?php
include "config.php";
?>
<!doctype html>
<html>
  <head>

  <?php
  if(isset($_POST['submit'])){

    if(!empty($_POST['lang'])) {

      $lang = implode(",",$_POST['lang']);

      // Insert and Update record
      $checkEntries = mysqli_query($con,"SELECT * FROM languages");
      if(mysqli_num_rows($checkEntries) == 0){
        mysqli_query($con,"INSERT INTO languages(language) VALUES('".$lang."')");
      }else{
        mysqli_query($con,"UPDATE languages SET language='".$lang."' ");
      }
 
    }

  }
  ?>
  </head>
  <body>
  <form method="post" action="">
    <span>Select languages</span><br/>
    <?php

    $checked_arr = array();

    // Fetch checked values
    $fetchLang = mysqli_query($con,"SELECT * FROM languages");
    if(mysqli_num_rows($fetchLang) > 0){
      $result = mysqli_fetch_assoc($fetchLang);
      $checked_arr = explode(",",$result['language']);
    }

    // Create checkboxes
    $languages_arr = array("PHP","JavaScript","jQuery","AngularJS");
    foreach($languages_arr as $language){

      $checked = "";
      if(in_array($language,$checked_arr)){
        $checked = "checked";
      }
      echo '<input type="checkbox" name="lang[]" value="'.$language.'" '.$checked.' > '.$language.' <br/>';
    }
    ?>
 
    <input type="submit" value="Submit" name="submit">
  </form>

  </body>
</html>

6. Conclusion

Next time when you use multiple checkboxes in your form then just initialize the name as an Array by putting [] in front and read it with loop when submitted.

How do I check if a checkbox is checked in PHP?

The isset() function is an inbuilt function in PHP which checks whether a variable is set and is not NULL. This function also checks if a declared variable, array or array key has null value, if it does, isset() returns false, it returns true in all other possible cases.

How can I check if a checkbox is checked?

In order to check if a checkbox is checked or unchecked, we can used the isSelected() method over the checkbox element. The isSelected() method returns a boolean value of true if the checkbox is checked false otherwise.

How to check if checkbox is unchecked in PHP?

When the checkbox is checked the value of the <input type=“checkbox” … /> is send with the post data, and if it isn't checked the value of the <input type=“hidden” … /> is send with the post data, so you can just check whether the value is 0 (unchecked) or 1 (checked).