Can an Option in a Select tag carry multiple values?

One way to do this, first one an array, 2nd an object:

    <select name="">
        <option value='{"num_sequence":[0,1,2,3]}'>Option one</option>
        <option value='{"foo":"bar","one":"two"}'>Option two</option>
    </select>

I achieved it by using the PHP explode function, like this:

HTML Form (in a file I named 'doublevalue.php':

    <form name="car_form" method="post" action="doublevalue_action.php">
            <select name="car" id="car">
                    <option value="">Select Car</option>
                    <option value="BMW|Red">Red BMW</option>
                    <option value="Mercedes|Black">Black Mercedes</option>
            </select>
            <input type="submit" name="submit" id="submit" value="submit">
    </form>

PHP action (in a file I named doublevalue_action.php)

    <?php
            $result = $_POST['car'];
            $result_explode = explode('|', $result);
            echo "Model: ". $result_explode[0]."<br />";
            echo "Colour: ". $result_explode[1]."<br />";
    ?>

As you can see in the first piece of code, we're creating a standard HTML select box, with 2 options. Each option has 1 value, which has a separator (in this instance, '|') to split the values (in this case, model, and colour).

On the action page, I'm exploding the results into an array, then calling each one. As you can see, I've separated, and labelled them so you can see the effect this is causing.