What potential issue arises when trying to select an option based on a value from a text file in a PHP form?

When selecting an option based on a value from a text file in a PHP form, the potential issue that arises is ensuring that the selected value matches one of the options available in the dropdown menu. To solve this, you can read the options from the text file into an array and then use that array to populate the dropdown menu. This way, you can validate the selected value against the options in the array to ensure a valid selection. 

<?php
// Read options from text file into an array
$options = file('options.txt', FILE_IGNORE_NEW_LINES);

// Output dropdown menu with options
echo '<select name="selected_option">';
foreach ($options as $option) {
    echo '<option value="' . $option . '">' . $option . '</option>';
}
echo '</select>';

// Validate selected option
if (isset($_POST['selected_option']) && in_array($_POST['selected_option'], $options)) {
    // Valid selection
    $selected_option = $_POST['selected_option'];
} else {
    // Invalid selection
    echo 'Invalid selection. Please choose a valid option.';
}
?>

Keywords

PHP form text file value selection

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