Simple encryption and decryption using base64

<?php
$key = "bala";
$enc = base64_encode ($key);
$dec = base64_decode ($enc);
echo 'Encrypted : '.$enc.'<br>';
echo 'Decrypted : '.$dec.'<br>';
?>

output:-

Encrypted : YmFsYQ==
Decrypted : bala

Simple ajax checkbox using jquery

index.php

if ($('.chkNumber:checked').length) {
          var chkId = '';
          $('.chkNumber:checked').each(function () {
            chkId += $(this).val() + ",";
          });
         chkId = chkId.slice(0, -1);
         //alert(chkId);

  var datastring='chkId='+chkId;
  //alert(datastring);

       $.ajax({
             type: "POST",
             url: "delete.php",
             data:datastring,
             cache:false,
             beforeSend: function()
             {
                 $("#signup_status").html("please wait....");
             },
             success:function(response)
             {
                 alert(response);
                 $("#signup_status").html(response)

             }

        });
        }
        else {
          alert('Nothing Selected');
        }

 
   
   
   
}
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checkbox code:-

<input name="checkbox[]" type="checkbox"   class="chkNumber" />


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retrieve checkbox :-


$chkId=$_POST['chkId'];
$count=explode(',',$chkId);
for($i=0;$i<$count[$i];$i++)
{
$del_qry="delete from gunning_3001 where id='$count[$i]'";
$res=mysql_query($del_qry) or die('Delete query does not work');
if($res)
{
  echo "Delete Records Successfully";

}
else
{
 echo "No Records Deleted";

}


}
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