Question

I have a PHP script designed to allow users to decide which language a page is displayed in. The information is stored in a cookie and then read when needed to display the correct content.

Currently, I use an HTML dropdown box to allow the user to select the language and then they must press the form submit button to set the cookie. How can I make it so when they select the language in the dropdown menu it automatically selects that and submits the form? I hope you can understand my question.

My current PHP code is:

<?php
$user_lang = null;
if (isset($_POST["setc"])) {
    $expire = time() + 60 * 60 * 24 * 30;
    setcookie("mycookie", $_POST["sel"], $expire);
    header("location: " . $_SERVER["PHP_SELF"]);
} else if (isset($_COOKIE["mycookie"])) {
    $user_lang = $_COOKIE["mycookie"];
}
?>

<meta charset='utf-8'>
<form action="<?php echo $_SERVER["PHP_SELF"]; ?>" method="post">
    <select name="sel" size="1">
        <option value="en"<?php echo (!is_null($user_lang) && $user_lang === "en" ? " selected" : ""); ?>>English</option>
        <option value="es"<?php echo (!is_null($user_lang) && $user_lang === "es" ? " selected" : ""); ?>>Español</option>
        <option value="fr"<?php echo (!is_null($user_lang) && $user_lang === "fr" ? " selected" : ""); ?>>Français</option>
        <option value="de"<?php echo (!is_null($user_lang) && $user_lang === "de" ? " selected" : ""); ?>>Deutsch</option>
    </select>
    <input name="setc" value="save setting" type="submit">
</form>

Answer 1

Change your select tag to:

<select name="sel" size="1" onchange="this.form.submit();">

to make the form submit when users selects a language.

If you wish to do that without JavaScript you can use multiple submit buttons method instead:

<input name="set_language[en]" value="English" type="submit">
<input name="set_language[es]" value="Español" type="submit">
<input name="set_language[fr]" value="Français" type="submit">
<input name="set_language[de]" value="Deutsch" type="submit">

Processing this form is simple as it is:

if (isset($_POST["set_language"])) {
    $language = key($_POST["set_language"]);
    // $language contains user-selected language code now
}

This can’t be done with a select field but without JavaScript or any other client-side scripting language.