PHP表单 - 没有提交按钮和ajax的单选按钮

Can I ask if it is possible to print result of a "checked" radio button without a submit button in php with ajax?

In my code below, I wanted to print "Thank you" when the "Yes" radio button is being clicked; and "Are you sure?" when the "No" button is being clicked without refreshing the page.

  <script>
            function getEmail(int){
            if(window.XMLHttpRequest){
                xmlhttp=new XMLHttpRequest();
                }else{
                xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
                }
                xmlhttp.onreadystatechange=function(){
                    if (xmlhttp.readyState==4 && xmlhttp.status==200){
                        document.getElementById("emailQ").innerHTML=xmlhttp.responseText;
                    }
                }
                            xmlhttp.open("GET", "index.php?q="+int, true);
                            xmlhttp.send();     
        }   
  </script>

        <div id = "emailQ">
        <li class="nav-header">Please confirm your facebook email:</li>
        <li><?php echo $_SESSION['EMAIL'];  ?></li>
            <form action="" method="post">
            <input type="radio" name="email" onclick="javascript: submit.getEmail()" value="Thank You"> Yes
            <input type="radio" name="email" onclick="javascript: submit.getEmail()" value="Are you sure?"> No
            </form> 
            <?php
                if(isset($_POST['email'])){
                    echo " ".$_POST['email'];
                }
            ?>

        </div>