Ajax and PHP with a while loop issue

Question

I have a ajax that needs to return some values, but if I use a while() to get all the result from my db, the return is "nothing". Where am I making mistake?

My Ajax script is posted below:

<script type="text/javascript" charset="utf-8">
  function addmsg(type, msg) {
    var obj = jQuery.parseJSON(msg);
    // Your count variable
    var count = obj.count;
    // Your not variable
    var not = obj.not;
    $('#msg_count').html(count);
    $('#notification').html(not);

  }

  function waitForMsg() {
    $.ajax({
      type: "GET",
      url: "notification/select.php",
      cache: false,
      timeout: 50000,

      success: function(data) {
        addmsg("new", data);
        setTimeout(
          waitForMsg,
          1000
        );
      },
      error: function(XMLHttpRequest, textStatus, errorThrown) {
        addmsg("error", textStatus + " (" + errorThrown + ")");
        setTimeout(
          waitForMsg,
          15000);
      }
    });
  };

  $(document).ready(function() {

    waitForMsg();

  });
</script>

My php script is posted below:

 $result = mysqli_query($con, "SELECT * from notification where tousername='$tousername' and isread = 0");

 while ($row = mysqli_fetch_array($result)) {
     $count = $result - > num_rows;
     $not = $row['notification_msg'];
     $res = [];
     $res['count'] = $count;
     $res['not'] = $not;
 }
 echo json_encode($res);

Does it literally return "nothing" (<-- this is a string), is the server not sending a response or does the server return nothing (<-- this is not a string)? — Tobias Xy
– Tobias Xy, Commented Feb 5, 2016 at 8:19

jeroen · Accepted Answer · 2016-02-05 08:19:14Z

4

You are overwriting your results variable in the loop:

while (...) {
  ...
  $res=[];
  ...
}

You probably want something like:

$res['count'] = $result->num_rows;
while($row = mysqli_fetch_array($result)) {
  $res[]['not'] = $row['notification_msg'];
}
echo json_encode($res);

answered Feb 5, 2016 at 8:19

jeroen

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8 Comments

Sanju Menon Over a year ago

Its not returning anything.

jeroen Over a year ago

@SanjuMenon Where does $tousername come from, do you get any results when you open notification/select.php directly in the browser?

Sanju Menon Over a year ago

it comes from the database. and iam comparing its with the logged in user.

jeroen Over a year ago

@SanjuMenon You should add that code and tell us what happens when you open notification/select.php in the browser.

Sanju Menon Over a year ago

Yes iam getting the proper output in select.php. This is the result...{"count":3,"0":{"not":"New Intender details entered 1"},"1":{"not":"New Intender details entered 2"},"2":{"not":"New Intender details entered 3"}}

|

Jakir Hossain · Accepted Answer · 2016-02-05 09:01:43Z

0

Overwrite your value with same index. you can write this.

while($row = mysqli_fetch_array($result)) {
$count = $result->num_rows;
$not=$row['notification_msg'];
$res=[];
$res['count'][] = $count;
$res['not'][] = $not; 
}

Or

while($row = mysqli_fetch_array($result)) {
$count = $result->num_rows;
$not=$row['notification_msg'];
$res=[];
$res[]['count'] = $count;
$res[]['not'] = $not; 
}

echo json_encode($res);

die();

Write your js addmsg() function.

function addmsg(type, msg) {
    var obj = jQuery.parseJSON(msg);
    // Your count variable
    for(prop in obj){
      var count = obj[prop][count];
      var not = obj[prop][not];
       $('#msg_count').html(count);
       $('#notification').html(not);
    }
  }

edited Feb 5, 2016 at 9:01

answered Feb 5, 2016 at 8:34

Jakir Hossain

2,51720 silver badges24 bronze badges

4 Comments

Sanju Menon Over a year ago

Do i need to change anything in the ajax script? like for example..adding an each..

Sanju Menon Over a year ago

iam sorry, its not returning anything. just blank. just seeing if i have made mistake

Sanju Menon Over a year ago

Basically iam doing a notification system like fb does. Its shows the count of unread messages. If we click the count, its shows the unread messages

Jakir Hossain Over a year ago

Write die() function end of your echo json_encode($res);

sagar chopada · Accepted Answer · 2016-02-05 09:12:17Z

-1

re-write your script

function waitForMsg(){
$.get("notification/select.php",function(callback){
console.log(callback); // here is your data in callback variabel you can in in console log
})
}

Replce this code with your php script.

 $result = mysqli_query($con, "SELECT * from notification where tousername='$tousername' and isread = 0");

       $res['count'] = $result->num_rows;
    while($row = mysqli_fetch_array($result)) {
      $res[]['not'] = $row['notification_msg'];
    }
    echo json_encode($res);

edited Feb 5, 2016 at 9:12

answered Feb 5, 2016 at 8:53

sagar chopada

3321 silver badge12 bronze badges

5 Comments

Sanju Menon Over a year ago

And what about my ajax script? Do i need to change anything?

Sanju Menon Over a year ago

Yes url is fine. But do i need to add $.each in the ajax to accomodate the while loop?

Sanju Menon Over a year ago

As of now my ajax script is written not to handle a loop. Am i correct?Am very new to ajax.

sagar chopada Over a year ago

yes your script is ok.. but you can use $.get("notification/select.php",function(callback){ "you can looping callback variable here in javascript"})

jeroen Over a year ago

Did you just literally copy my answer but without the explanation?

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