<script>
$(document).ready(function() {
$("#username_ID").blur(function(e){
alert("BLUR");
});
});</script>
<div id='newaccount'>
<form id='registerform' action='registeraccount.php' method='post'>
Name: <input type='text' name='firstname' /> </br>
Username: <input id='username_ID' type='text' name='username' /> </br>
<input type='submit' value='Submit Comment' />
</form>
</div>