$(document).ready(function(){
  $.validate({"form" : "#testForm","validateOnEvent":true});
});

<form id="testForm">
<p>
Email
<input name="email" data-validation="email" data-validation-event="keypress"> // data-validation-event is used for event base elements
</p>
<p>
Username
<input name="user" data-validation="length alphanumeric"
 data-validation-length="3-12"
 data-validation-error-msg="User name has to be an alphanumeric value (3-12 chars)" data-validation-event="keypress">
</p>
</form>