Php ajax Poll system with multiple answer

I am trying to make a poll system using php, mysql and ajax. I have created poll table from database.

id
answer
vote

I want users to increase their answers and i have created a simple javascript function like this DEMO

<div class="inputsl">
   <div class="inputt"><input type="text" id="createPoll" name="mypoll" class="myinput"></div>
   <div class="inputt"><input type="text" id="createPoll" name="mypoll" class="myinput"></div>
   <div class="inputt"><input type="text" id="createPoll" name="mypoll" class="myinput"></div>
   <div class="inputt"><input type="text" id="createPoll" name="mypoll" class="myinput"></div>
</div>

I have also created ajax function for inserting answers

$("body").on("click",".insertp", function(){
       var poll = $("#createPoll").val();
       var dataPoll = 'poll=' + poll;
       $.ajax({
           type:'POST',
           url:'/requests/postPoll',
           data: dataPoll,
           cache: false,
           beforeSend: function(){},
           sucess: function(){
               console.log("Success!");
           }   
        });
     });

and the postPoll.php functions

<?php 
include_once '../inc/inc.php';
if(isset($_POST['poll'])){
    $poll = mysqli_real_escape_string($db, $_POST['poll']);
    if($poll){
foreach($poll as  $setPoll){
      $insertPollfromData = $InSert->Insert_Poll($uid, $setPoll);
    }
    }
}
?>

Now, i want to insert multiple answer from poll table but my postPoll.php gives me this error:

Warning: Invalid argument supplied for foreach() in

How can i insert multiple poll from database ? Anyone can help me here ? Thank you very much in advance for your help.