在足下是实训的注册表的源代码：

<!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>注册表</title>
<script type="text/javascript" src="check.js">
</script>
</head>

<body>
   
    <form action="" method="get" id="form_adminstration">
        <table id="adiminstration" align="center">
           <tr width="600">
               <td colspan="3" align="center"><font size="+2"><b>注册     </b></font></td>
            </tr>

            <tr width="600">
               <td align="right" width="200">用户名:</td>
                <td align="left" width="200"><input type="text" id="userName" align="left" onblur="CheckUserName()" /></td>
                <td width="200"><div align="left" id="userNameAttention"></div></td>
            </tr>

            <tr width="600">
               <td align="right" width="200">密码:</td>
                <td align="left" width="200"><input type="password" id="password" align="left" onblur="CheckPassword()"/></td>
                <td width="200"><div align="left" id="passwordAttention"></div></td>
            </tr>

            <tr width="600">
               <td align="right" width="200">确认密码:</td>
                <td align="left" width="200"><input type="password" id="passwordConfirm" align="left" onblur="CheckPasswordConfirm()" /></td>
                <td width="200"><div align="left" id="passwordConfirmAttention"></div></td>
            </tr>

            <tr width="600">
               <td align="right" width="200">邮箱:</td>
                <td align="left" width="200"><input type="text" id="mailbox" align="left" onblur="CheckMailbox()"/></td>
                <td width="200"><div align="left" id="mailboxAttention"></div></td>
            </tr>

            <tr width="600">
                <td colspan="3" align="center">
                    <label><input type="button" id="confirm" value="注册" style="90px" onclick="Check()"/></label>
                    <label><input type="reset" id="concel" value="取消" style="90px" /></label>
                </td>
            </tr>
        </table>
    </form>
</body>
</html>

// JavaScript Document

   function CheckUserName()
   {
       if(document.getElementById("userName").value == "")
       {
           document.getElementById("userNameAttention").innerHTML = "<font>用户名不能为空</font>";
       }
       else
       {
           document.getElementById("userNameAttention").innerHTML = "<font></font>";
       }
   }

   
   function CheckPassword()
   {
       if(document.getElementById("password").value == "")
       {
           document.getElementById("passwordAttention").innerHTML = "<font>密码不能为空</font>";
       }
       else
       {
           document.getElementById("passwordAttention").innerHTML = "<font></font>";
       }
   }

   
   function CheckPasswordConfirm()
   {
       if(document.getElementById("passwordConfirm").value == "")
       {
           document.getElementById("passwordConfirmAttention").innerHTML = "<font>确认密码不能为空</font>";
       }
       else
       {
           document.getElementById("passwordConfirmAttention").innerHTML = "<font></font>";
           if(document.getElementById("passwordConfirm").value != document.getElementById("password").value)
           {
               document.getElementById("passwordConfirmAttention").innerHTML = "<font>密码输入不一致</font>";
           }
           else
           {
               document.getElementById("passwordConfirmAttention").innerHTML = "<font></font>";
           }
       }
   }

   
   function CheckMailbox()
   {
       if(document.getElementById("mailbox").value == "")
       {
           document.getElementById("mailboxAttention").innerHTML = "<font>邮箱不能为空</font>";
       }
       else
       {
           document.getElementById("mailboxAttention").innerHTML = "<font></font>";
           var reg = /^([a-zA-Z0-9_-])+@([a-zA-Z0-9_-])+((.[a-zA-Z0-9_-]{2,3}){1,2})$/;
           if(!reg.test(document.getElementById("mailbox").value))
           {
               document.getElementById("mailboxAttention").innerHTML = "<font>邮箱格式不正确</font>";
           }
           else
           {
               document.getElementById("mailboxAttention").innerHTML = "<font></font>";
           }
       }
   }

   
   function Check()
   {
       CheckUserName();
       CheckPassword();
       CheckPasswordConfirm();
       CheckMailbox();
       var reg = /^([a-zA-Z0-9_-])+@([a-zA-Z0-9_-])+((.[a-zA-Z0-9_-]{2,3}){1,2})$/;
       if((document.getElementById("userName").value!="")&&(document.getElementById("password").value != "")
       &&(document.getElementById("passwordConfirm").value != "")&&(document.getElementById("mailbox").value != "")
       &&(reg.test(document.getElementById("mailbox").value)))
       {
           alert("提交成功");
       }
       else
       {
           alert("提交错误");
       }
   }