<script src="../js/jquery.js" type="text/javascript"></script> <script src="../js/jquery.validate.js" type="text/javascript"></script> <script src="./js/jquery.metadata.js" type="text/javascript"></script> $().ready(function() {  $("#signupForm").validate(); }); <form id="signupForm" method="get" action="">     <p>         <label for="firstname">Firstname</label>         <input id="firstname" name="firstname" class="required" />     </p>  <p>   <label for="email">E-Mail</label>   <input id="email" name="email" class="required email" />  </p>  <p>   <label for="password">Password</label>   <input id="password" name="password" type="password" class="{required:true,minlength:5}" />  </p>  <p>   <label for="confirm_password">确认密码</label>   <input id="confirm_password" name="confirm_password" type="password" class="{required:true,minlength:5,equalTo:'#password'}" />  </p>     <p>         <input class="submit" type="submit" value="Submit"/>     </p> </form>