Ajax check customer mail address

Question

I am using this below code for check customer exist in database or not. it's working fine but it reload the page. can anyone suggest some ajax for reloading

<script type="text/javascript">
function emailcheck(email){
document.getElementById("myform").submit();
}

</script>

<?php //print_r($_POST['email']);

 echo $email=$_POST['email'];
$con = mysql_connect("localhost","root","password");

   if (!$con)
  {
     die('Could not connect: ' . mysql_error());
  }
       mysql_select_db("magento", $con);

        $sql = "SELECT `email` FROM `customer_entity` WHERE `email`='".$email."'" or die(mysql_error());
       $select = mysql_query($sql,$con);

       $result=mysql_fetch_array($select);


      echo $row = mysql_num_rows($select);

            if ($row > 0)  
          {
            echo 'This email Id is already exixst';  
          }
             else 
          {
             echo 'unavailable';
          } 
?>
        <form id="myform" name ="myform" method="POST">
                <input STYLE="WIDTH: 68%;MARGIN-LEFT: 12%;background-color: white;" placeholder="Email Address" type="email" name="email" id= "email" class="input-text " required />   

                <button class="button" onclick="emailcheck();"/> <span><span><?php echo $this->__('Submit') ?></span></span> </button>
        </form>

Answer 1

Let me stop you there, you don't connect directly in your database like this, this is very bad practice, and can potentially be dangerous for your store if you expose database details.

Follow this guide, it covers in details what you are after: http://www.atwix.com/magento/ajax-validation/

Answer 2

Despite the fact that this is very bad for security if this is intended to be used by your customers in the frontend: It can be used to retrieve information about your registered customers and then brute-force their passwords.

Apart from that you need the following to create such a AJAX check:

1. Create a custom controller where you send the request to
2. Call that custom controller via AJAX request

Answer 3

Since you are using magento framework, you need to do it the 'correct' way

To check if email customer email exist

$customer = Mage::getModel('customer/customer');
$customer->setWebsiteId(Mage::app()->getWebsite()->getId());

$customer->loadByEmail($email);

if ($customer->getId()) {
    //true
}
else{
  //false
}

Since magento uses prototype JS and the validation library, you could create you own validation class see Magento form field AJAX validation