What potential issue can arise when using conditional statements in PHP to execute scripts based on user numbers?

One potential issue that can arise when using conditional statements in PHP to execute scripts based on user numbers is the need to handle cases where the user input is not a valid number. This can lead to unexpected behavior or errors in the script. To solve this issue, it is important to validate the user input before using it in conditional statements to ensure it is a numeric value.

$userInput = $_POST['user_input'];

if (is_numeric($userInput)) {
    // Execute script based on user input
    if ($userInput > 10) {
        // Script for user input greater than 10
    } else {
        // Script for user input less than or equal to 10
    }
} else {
    echo "Invalid input. Please enter a numeric value.";
}