如何在单页主页上发布表单数据

<form name="makeup" action="index.php" method="post">
                <select id="skin_shade">
                    <option value="skin_shade_1">Dark</option>
                    <option value="skin_shade_2">Light</option>
                </select></br>
                Acne:<input type="checkbox" value="acne"/></br>
                Oil:<input type="checkbox" value="oily"/></br>
                Straight Hair:<input type="checkbox" value="straight"/></br>

            <input type="submit" value="Submit"/>
        </form>

<?php
echo $_POST['skin_shade']?>;

I get no output after I hit submit except for the form resetting.

Change <select id="skin_shade"> to <select name="skin_shade"> ?