注册页面的js验证

简单的用户注册页面：(html)

包含用户名格式验证、邮箱格式验证、确认密码一致性验证和必填项验证。(纯javascript)

 <center>
     <h1>用户注册</h1>
     <hr>
     <SCRIPT type="text/javascript">
     function isEmail(strEmail) {
         if (strEmail.search(/^\w+((-\w+)|(\.\w+))*\@[A-Za-z0-9]+((\.|-)[A-Za-z0-9]+)*\.[A-Za-z0-9]+$/) != -1)
             return true;
         else {
             alert("邮箱格式不对");
             return false;
         }
     }

     function isUsername(un) {
         if (un.search(/^[a-zA-Z0-9_]{1,20}$/) != -1) return true;
         else {
             alert("用户名只能由1～20位长度的数字、英文字母或者下划线组成");
             return false;
         }
     }

     function checkSubmit() {
         if (document.getElementById("username").value == "") {
             alert("请填写用户名!");
             return false;
         }
         if (document.getElementById("email").value == "") {
             alert("请填写邮箱!");
             return false;
         }
         var pwd1 = document.getElementById("password1");
         var pwd2 = document.getElementById("password2");
         if (pwd1.value == "") {
             alert("请填写密码!");
             return false;
         }
         if (pwd2.value == "") {
             alert("请再次填写密码!");
             return false;
         }
         if (pwd1.value != pwd2.value) {
             alert("密码不一致");
             return false;
         }
     }
     </SCRIPT>
     <form name="Register" method="post">
         <table>
             <tr>
                 <td align="center">用户名*:</td>
                 <td>
                     <input type="text" name="username" id="username" onblur="isUsername(this.value)">
                 </td>
             </tr>
             <tr>
                 <td align="center">邮箱*:</td>
                 <td>
                     <input type="text" name="email" id="email" onblur="isEmail(this.value)">
                 </td>
             </tr>
             <tr>
                 <td align="center">密码*:</td>
                 <td>
                     <input type="password" id="password1" name="password1">
                 </td>
             </tr>
             <tr>
                 <td align="center">密码确认*:</td>
                 <td>
                     <input type="password" name="password2" id="password2">
                 </td>
             </tr>
             <tr>
                 <td align="center"><a href="/horizon/auth/login">返回 </a></td>
                 <td>
                     <input type="submit" value="注册!" onclick="return checkSubmit()">
                 </td>
             </tr>
         </table>
     </form>
 </center>