html代码例如以下：

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "​​http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd​​">

<html xmlns="​​http://www.w3.org/1999/xhtml​​">

<head>

  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

  <title></title>

  <link href="css/style.css" rel="stylesheet" type="text/css" />

  <!-- 引入jQuery -->

  <script src="../scripts/jquery-1.3.1.js" type="text/javascript"></script>

  <script type="text/javascript">

     //<![CDATA[

     $(function(){

        //假设是必填的，则加红星标识

        $("form :input.required").each(function(){

           var $required = $("<strong class='high'> *</strong>"); //创建元素

           $(this).parent().append($required); //然后将它追加到文档中

        });

        //文本框失去焦点后

        $('form :input').blur(function(){

           var $parent = $(this).parent();

           $parent.find(".formtips").remove();

           //验证username

           if($(this).is('#username')){

             if(this.value=="" || this.value.length < 6){

                var errorMsg = '请输入至少6位的username.';

                $parent.append('<span class="formtips onError">'+errorMsg+'</span>');

             }else{

                var okMsg = '输入正确.';

                $parent.append('<span class="formtips onSuccess">'+okMsg+'</span>');

             }

           }

           //验证邮件

           if($(this).is('#email')){