选择数据Ajax

I would like to select streamitem_id from my insert.php and add it to my existing post div. I'm needing the id of the post made so I can add it into my div so later when I add my delete button it will delete the post and the div that holds it. Hope I've made sense and I can do this with what I have as I'm trying to learn but it is a difficult language like any when first starting out.

AJAX

 <script>
    $(document).ready(function(){
        $("form#myform").submit(function(event) {
            event.preventDefault();
            var content = $("#toid").val();
            var newmsg = $("#newmsg").val();

            $.ajax({
                type: "POST",
                url: "insert.php",
                data: "toid=" + content + "&newmsg=" + newmsg,
                success: function(){
                    $("#homestatusid").prepend("<div id='divider-"+WHERE MY STREAMITEM_ID NEEDS TO BE+"'><div class='userinfo'>"+newmsg+"</div></div>");
                }
            });
        });
    });
    </script>

INSERT.PHP

$check = "SELECT streamitem_id FROM streamdata WHERE streamitem_id=$user1_id";
        $check1     =    mysql_query($check);
        $check2     =    mysql_num_rows($check1);
    echo $check2;

success: function(response){
    $("#homestatusid").prepend("<div id='divider-"+response+"'><div class='userinfo'>"+newmsg+"</div></div>");
}

In your javascript should be

       $.ajax({
            type: "POST",
            url: "insert.php",
            data: {toid:content, newmsg: newmsg}, # pay attention to this line
            success: function(data){
                $("#homestatusid").prepend("<div id='divider-"+data+"'><div class='userinfo'>"+newmsg+"</div></div>");
            }
        });

PHP

$toid = isset($_POST['toid']) ? $_POST['toid'] : null;
$newmsg = isset($_POST['newmsg']) ? $_POST['newmsg'] : null;

And do not use mysql_* since it deprecated

The first argument passed to the success callback is the responseText from the AJAX call. Modify your jQuery code to this:

success: function(responseText){
    $("#homestatusid").prepend("<div id='divider-"+responseText+"'><div class='userinfo'>"+newmsg+"</div></div>");
    // I'm assuming that insert.php returns just the ID you're interested in
}