PHP+JAVASCRIPT+正则表达式更改密码的实例

<?php //更改密码的编辑界面//加载文件，判断是否登陆include('menu.php');include('head.php');?><form method="post" name="regform" action="gr_ggmm_update.php"><script type="text/javascript"> //更新前的格式判断function regcheck(){var regpassword=/^[A-Za-z0-9]+$/;var password1=document.regform.password1.value;var password2=document.regform.password2.value;var password3=document.regform.password3.value;if (!password1.match(regpassword)) {alert("密码应由英文或数字组成");document.regform.password1.focus();return false;}if (!password2.match(regpassword)) {alert("密码应由英文或数字组成");document.regform.password2.focus();return false;}if (!password3.match(regpassword)) {alert("密码应由英文或数字组成");document.regform.password3.focus();return false;}if (password2!=password3) {alert("两次密码不一致");document.regform.password2.focus();return false;}}</script><table width=35% border="0" bordercolor="#0099FF" align="center"><caption><?php echo $_SESSION['ywclrealname'] ?> 更改密码</caption><tr><td width="27%" align="right">原密码：</td><td width="40%"><input type="password" name="password1"  autofocus></td><td width="33%">例：ae4D5c</td></tr><tr>  <td align="right">新密码：</td>  <td><input type="password" name="password2" ></td>  <td>例：ae4D5c</td>    </tr><tr>  <td align="right">新密码：</td>  <td><input type="password" name="password3" ></td>  <td>例：ae4D5c</td>   <tr>  <td align="right"><input type="reset" name="submit2" value="清空" /></td>  <td align="center">    <input type="submit" name="submit" value="更新" onClick="return regcheck()"/>  </td>  <td align="right"> </td>    </tr></table></form><?phpinclude('foot.php');?>