PHP Select Option

Summary: in this tutorial, you will learn how to use the <select> element to create a drop-down list and a list box and how to get the selected values from the <select> element in PHP.

A quick introduction to the <select> element

The <select> is an HTML element that provides a list of options. The following shows how to define a <select> element in HTML:

<label for="color">Background Color:</label> <select name="color" id="color"> <option value="">--- Choose a color ---</option> <option value="red">Red</option> <option value="green">Green</option> <option value="blue">Blue</option> </select>
Code language: HTML, XML (xml)

The <select> element has two important attributes:

  • id – the id associates the <select> element with a <label> element
  • name – the name attribute associates with the value for a form submission.

The <option> element nested inside the <select> element defines an option in the menu. Each option has a value attribute. The value attribute stores data submitted to the server when it is selected.

If an option doesn’t have the value attribute, the value attribute defaults to the text inside the <option> element.

To select an option when the page loads for the first time, you can add the selected attribute to the <option> element.

The following example selects the Green option when the page first loads:

<label for="color">Background Color:</label> <select name="color" id="color"> <option value="">--- Choose a color ---</option> <option value="red">Red</option> <option value="green" selected>Green</option> <option value="blue">Blue</option> </select>
Code language: HTML, XML (xml)

Getting the selected value from a <select> element

We’ll create a form that uses a <select> element.

First, create the following folders and files:

├── css | └── style.css ├── inc | ├── footer.php | ├── get.php | ├── header.php | └── post.php └── index.php
Code language: JavaScript (javascript)

Second, place the following code in the header.php file:

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" href="css/style.css"> <title>PHP select option</title> </head> <body class="center"> <main>
Code language: HTML, XML (xml)

Third, place the following code in the footer.php file:

</main> </body> </html>
Code language: HTML, XML (xml)

Fourth, add the following code to the get.php file to create a form that has one <select> element with a submit button:

<form action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']) ?>" method="post"> <div> <label for="color">Background Color:</label> <select name="color" id="color"> <option value="">--- Choose a color ---</option> <option value="red">Red</option> <option value="green" selected>Green</option> <option value="blue">Blue</option> </select> </div> <div> <button type="submit">Select</button> </div> </form>
Code language: HTML, XML (xml)

The form uses the POST method to submit data to the webserver.

Finally, add the following code to the post.php file:

<?php $color = filter_input(INPUT_POST, 'color', FILTER_SANITIZE_STRING); ?> <?php if ($color) : ?> <p>You selected <span style="color:<?php echo $color ?>"><?php echo $color ?></span></p> <p><a href="index.php">Back to the form</a></p> <?php else : ?> <p>You did not select any color</p> <?php endif ?>
Code language: HTML, XML (xml)

To get the selected value of the <select> element, you use the $_POST superglobal variable if the form method is POST and $_GET if the form method is GET.

Alternatively, you can use the filter_input() function to sanitize the selected value.

If you select the first option of the <select> element, the selected value will be empty. Otherwise, the selected value is red, green, or blue.

Select with multiple options

To enable multiple selections, you add the multiple attribute to the <select> element:

<select name="colors[]" id="colors" multiple> ... </select>
Code language: HTML, XML (xml)

When you select multiple options of a <select> element and submit the form, the name will contain multiple values rather than a single value. To get multiple selected values, you add the square brackets ([]) after the name of <select> element.

Let’s take a look at an example of using a <select> element with multiple selections.

First, create the following folders and files:

. ├── css | └── style.css ├── inc | ├── footer.php | ├── get.php | ├── header.php | └── post.php └── index.php
Code language: JavaScript (javascript)

Second, place the following code into the header.php file:

<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" /> <meta name="viewport" content="width=device-width, initial-scale=1.0" /> <title>PHP Listbox</title> <link rel="stylesheet" href="css/style.css"> </head> <body class="center"> <main>
Code language: HTML, XML (xml)

Third, add the following code to the footer.php file:

</main> </body> </html>
Code language: HTML, XML (xml)

Fourth, include the header.php and footer.php files in the index.php:

<?php require __DIR__ . '/inc/header.php'; $request_method = strtoupper($_SERVER['REQUEST_METHOD']); if ($request_method === 'GET') { require __DIR__ . '/inc/get.php'; } elseif ($request_method === 'POST') { require __DIR__ . '/inc/post.php'; } require __DIR__ . '/inc/footer.php';
Code language: HTML, XML (xml)

If the HTTP request is GET, the index.php file will show a form from the get.php file. When the form is submitted, the post.php file will handle the form submission.

Fifth, create a form that contains a <select> element with the multiple attribute in the get.php file. The name of the <select> element has an opening and closing square bracket [] so that PHP can create an array that holds the select values.

<form action="<?php echo htmlspecialchars($_SERVER['PHP_SELF']) ?>" method="post"> <div> <label for="colors">Background Color:</label> <select name="colors[]" id="colors" multiple> <option value="red">Red</option> <option value="green">Green</option> <option value="blue">Blue</option> <option value="purple">Purple</option> <option value="magenta">Magenta</option> <option value="cyan">Cyan</option> </select> </div> <div> <button type="submit">Submit</button> </div> </form>
Code language: HTML, XML (xml)

Finally, handle the form submission in the post.php file:

<?php $selected_colors = filter_input( INPUT_POST, 'colors', FILTER_SANITIZE_STRING, FILTER_REQUIRE_ARRAY ); ?> <?php if ($selected_colors) : ?> <p>You selected the following colors:</p> <ul> <?php foreach ($selected_colors as $color) : ?> <li style="color:<?php echo $color ?>"><?php echo $color ?></li> <?php endforeach ?> </ul> <p> </p> <?php else : ?> <p>You did not select any color.</p> <?php endif ?> <a href="index.php">Back to the form</a>
Code language: HTML, XML (xml)

The post.php file uses the filter_input() function to get the selected colors as an array. If you select one or more colors, the post.php file will display them.

Summary

  • Use the <select> element to create a dropdown list.
  • Use the multiple attribute to create a list that allows multiple selections.
  • Use $_POST to get the selected value of the select element if the form method is POST (or $_GET if the form method is GET).
  • Add square brackets([]) after the name of the <select> element to get multiple selected values.
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