使用Ajax插入和获取数据插入有效，但获取功能无效

Question

I'm using ajax insert and fetch the data from the database, insert is working perfectly but fetching part is not working give a feedback to fix this issues.

<script>
            $(document).ready(function(){
                $("#button").click(function(e){
                   e.preventDefault();
                    var postId=$("#postId").val();
                    var userId=$("#userId").val();
                    var postComm=$("#postComments").val();

                    $.ajax({
                        url:'../validate/inserPostComm.php',
                        method:'POST',
                        data:{
                            poId:postId,
                            usId:userId,
                            poco:postComm
                        },
                       success:function(data){
                           //alert(data);
                           displayFromDatabase();
                           $("#postComments").val('');
                       }
                    });
                });
            });

              function displayFromDatabase(){
                    var postId=$("#postId").val();
                        alert(postId);
                  $.ajax({
                      url: "../validate/getComments.php",
                      type: "POST",
                      async: false,
                      data: {
                            poId:postId,
                      },
                      success: function(data){
                        ('#display_area').html(data);  
                   }
                  });
              }
          </script>

and this my html code to retrieve the fetching details from database.

<li>
  <div id="display_area">

   </div>
</li> 
<button type="button" id="button"><i class="fa fa-paper-plane"></i></button>

and also i attached my php code through the ajax i'm passing the id and i'm get the details according to the id.

$postId=$_POST["poId"];

$getPostCom=$postComments->getPostComm($postId,"../");

while($PostComments=mysqli_fetch_assoc($getPostCom))
 {

    ?>


    <div class="comet-avatar">
        <img src="<?php echo $PostComments["u_image"]; ?>" alt="">
    </div>
        <div class="we-comment">
            <div class="coment-head">
                <h5><a href="user-profile.php?user_id=<?php echo $PostComments["u_id"]; ?>" title=""><?php echo $PostComments["u_fname"]; ?> <?php echo $PostComments["u_lname"]; ?></a></h5>
            </div>
                <p><?php echo $PostComments["p_comments"]; ?></p>
        </div>

<?php
 }
    exit();
?>

Answer 1

Yes this code working perfectly but i missed the $ in the success block.

<script>
            $(document).ready(function(){
                $("#button").click(function(e){
                   e.preventDefault();
                    var postId=$("#postId").val();
                    var userId=$("#userId").val();
                    var postComm=$("#postComments").val();

                    $.ajax({
                        url:'../validate/inserPostComm.php',
                        method:'POST',
                        data:{
                            poId:postId,
                            usId:userId,
                            poco:postComm
                        },
                       success:function(data){
                           //alert(data);
                           displayFromDatabase();
                           $("#postComments").val('');
                       }
                    });
                });
            });

              function displayFromDatabase(){
                    var postId=$("#postId").val();
                        alert(postId);
                  $.ajax({
                      url: "../validate/getComments.php",
                      type: "POST",
                      async: false,
                      data: {
                            poId:postId,
                      },
                      success: function(data){
                        $('#display_area').html(data);  
                   }
                  });
              }
          </script>