用PHP内容显示div的Javascript函数只会闪烁

I've written a javascript function to show a PHP within a Div. It seems to work, except that the php to be shown only flashes up for a brief second. Is there any way to get it to stay shown until I select an option to close it.

Many thanks

    function showBiog(keysop){
$.ajax({
                url: 'test2.php?number=' + keysop,
                type: 'POST',
                dataType: 'html',
                data: $('#SubmitForm').serialize(),
                success: function(content)
                {
                    $("#DisplayDiv").html(content);
                }  
        });
        event.preventDefault();
$('#submit_btn_id').click();
}