username availability PDO not working - php

Question

This is my HTML Code
<input type="text" class="form-control" id="stfmail" name="staffmail" placeholder="E-Mail" required="required"><span id="result"></span>
In jQuery Ajax
<script type="text/javascript">
$(document).ready(function(){
$("#stfmail").keyup(function() {
var name = $(this).val();
if(name.length > 1)
{
$("#result").html('checking...');
$.ajax({
type : 'POST',
url : '../include/check_availability.php',
data : $(this).serialize(),
success : function(data)
{
$("#result").html(data);
}
});
return false;
}
else
{
$("#result").html('');
}
});
});
</script>
PHP
if($_POST)
{
$username = $_POST['name'];
$ob->useravailable($username);
}
public function useravailable($username)
{
$stmt=$this->conn->prepare("select user_name from users where user_name=:uname and delet='0'");
$stmt->execute(array(':uname'=>$username));
if($stmt->rowCount()>0)
{
echo "<span style='color:brown;'>Sorry username already taken !!!</span>";
}
else
{
echo "<span style='color:green;'>available</span>";
}
}
Here i type a username..but in useravailable function only else part is working.. I type Existing username it works the else part available message is shown..
Please help me
thanks

Answer 1

<script type="text/javascript">
$(document).ready(function(){
$("#stfmail").keyup(function() {
var name = $(this).val();
if(name.length > 1)
{
$("#result").html('checking...');
$.ajax({
type : 'POST',
url : '../include/check_availability.php',
data : $(this).serialize(),
success : function(data)
{
$("#result").html(data);
if(data) {
$(".redbold").html('already this username is there ').show();
$("#username").focus();
}
}
});
return false;
}
else
{
$("#result").html('');
}
});
});
</script>
if($_POST)
{
$username = $_POST['name'];
$query = mysql_query("SELECT user_name from users where user_name ='".$username ."' ", $con);
while ($row = mysql_fetch_assoc($query)) {
echo $row['user_name '];
}
}