Mailto using Javascript?

Your code should look like this instead:

<script>
function sendMail()
{
    var yourMessage = document.getElementById("message").value;
    var subject = document.getElementById("selectList").value;
    document.location.href = "mailto:[email protected]?subject="
        + encodeURIComponent(subject)
        + "&body=" + encodeURIComponent(yourMessage);
}
</script>