How to Process a Checkbox With PHP

You can use PHP to process the value of a checkbox after it has been clicked or not in an HTML form. This is helpful when you want to let your Web page visitor select one or more options from a list or to answer yes/no type of questions. If a checkbox is clicked, its value is set in the "$_POST" array, which is sent to the Web page that processes the submitted form.

Instructions

1. Open the HTML file that you want to use a checkbox form in. Use a text editor such as Windows Notepad.

2. Create an HTML form with an input type of "checkbox". Include a "Submit" button for the user to click after she's made her selection. For example, "<form action="mypage.php" method="post">text of question<input type="checkbox" name="myvariable" value="Yes"/><input type="submit" name="myform" value="Submit"/></form>" stores the checkbox status in the "myvariable" variable and redirects the user to the Web page "mypage.php" when the "Submit" button is clicked.

3. Save and close the HTML file.

4. Open your PHP file.

5. Process the checkbox by using the "isset" function to check if a value for the checkbox was set in the "$_POST" array. If the checkbox was clicked, then the form's variable will have a value equal to what the "value=" was set to in the form. If the checkbox was unchecked, then the variable won't be set and "isset" will return false. For example, "<?php if(isset($_POST['myvariable'])){ $myvalue = $_POST['myvariable']; } else { $myvalue = "checkbox not checked"; } ?>".

6. Save the PHP file.

Tips & Warnings

• PHP code must be contained within "<?php" and "?>" tags.

References

• W3Schools.com: HTML Forms and Input

Resources

• HTML Form Guide: Handling Checkbox in a PHP Form Processor