Firefox中的$。（ajax）不会从输入发送RADIO

I have thise code in my form (action="index.php" method="post" id="reform"):

   <input class="radio-input" id="reg_title1" type="radio" name="title" value="Mr." checked="checked">
   <input class="radio-input" id="reg_title2" type="radio" name="title" value="Mrs.">

When passing this through:

                $.ajax({
                    type: 'post',
                    url: 'reg.php',
                    data: $("#regform").serialize(),
                    success: function (response) {
                        if(response == 'success') {
                            location.reload();
                        }
                        else {
                            alert(response);
                        }
                    }
                });
                e.preventDefault();

In Safari I get the "title" value. In Firefox it mysteriously is not posted! I made var_dump($_POST); and it shows the title value in the array in Safari, but not in Firefox. What is wrong with sending radio content?