Username validations in php and ajax

hi all

I new to php

I need a script of php which needs to validate my username as fallows

->Allows only Alphabets

->need not be empty

I need dynamic validation i.e using AJAX and PHP together.

kindly help me to solve this

Regards

Sunil

You could validate the username using preg_match, something like.

$username = $_GET['username'];
if(preg_match('/^[a-zA-Z]+$/', $username)) {
   echo(json_encode(array('Response'=>1)));
} else {
   echo(json_encode(array('Response'=>0)));
}

then it would be easy picking up the response using a library like jQuery, which has the $.getJSON function.

<script type='text/javascript'>
   $(document).ready(function() {
      $('input[name=username]').bind('keyup', function() {
         $.getJSON('validation_file.php', {username: $(this).val()}, function(data) {
            var response = parseInt(data[0].Response);
            if(response === 1) {
                // valid
            } else {
                // not valid
            }
         });
      });
   });
</script>
<input type='text' name='username'>

first you attach the keyup event to your field, which means the following function fires whenever the user releases a keyboard key, with the field in focus. It then checks the validation file (which contains the php part) and sends the username along in a $_GET variable. The php script then validates it using reg ex an returns an response array encoded as json. Please note i have not tested this code and it is highly likely to have flaws in it