PHP实现当前登录用户修改密码

<?php// 如果提交了表单if (isset($_POST['edit'])) {$pwd = trim($_POST['pwd']);$pwd1 = trim($_POST['pwd1']);$pwd2 = trim($_POST['pwd2']);$sql = "select * from `admin` where password='".md5($pwd)."' and username='".$_SESSION['username']."'";//将$sql交由conn.php处理了require_once('../../conn.php');if (mysqli_num_rows(mysqli_query($conn,$sql))) {if ($pwd1==$pwd2) {$sql="update `admin` set password='".md5($pwd2)."' where username='".$_SESSION['username']."'";//将$sql交由conn.php处理了require_once('../../conn.php');if (mysqli_query($conn,$sql)) {echo "<div class='op-alert'>恭喜，密码修改成功！</div><div id='dialog-mask'></div>";echo '<meta http-equiv=refresh content=2;url="user_edit.php">';}}else {echo "<div class='op-alert'>两次输入的新密码不同，请重新输入!</div><div id='dialog-mask'></div>";echo '<meta http-equiv=refresh content=2;url="user_edit.php">';}}else {echo "<div class='op-alert'>旧密码不正确，请重新输入!</div><div id='dialog-mask'></div>";echo '<meta http-equiv=refresh content=2;url="user_edit.php">';}}?>