编辑和删除始终不成功，求大神
<h2>编辑管理员</h2>
<form action="doAdminAction.php?act=editAdmin&id=<?php echo $id;?>" method="post">
<table width="70%" border="1" cellpadding="5" cellspacing="0" bgcolor="#cccccc">
<tr>
<td align="right">管理员名称</td>
<td><input type="text" name="username" placeholder="<?php echo $row['username'];?>"/></td>
</tr>
<tr>
<td align="right">管理员密码</td>
<td><input type="password" name="password" placeholder="<?php echo $row['password'];?>"/></td>
</tr>
<tr>
<td align="right">管理员邮箱</td>
<td><input type="text" name="email" placeholder="<?php echo $row['email'];?>"/></td>
</tr>
$act=$_REQUEST['act'];
@$id=$_REQUEST['id'];
if($act=="logout"){
logout();
}elseif($act=="addAdmin"){
$mes=addAdmin();
}elseif($act=="editAdmin"){
$mes=editAdmin($id);
}elseif($act=="delAdmin"){
$mes=delAdmin($id);
function editAdmin($id){
$arr=$_POST;
$arr['password']=md5($_POST['password']);
if(update("imooc_admin",$arr,"id={$id}")){
$mes="编辑成功！<a href='listAdmin.php'>查看管理员列表</a>";
}else{
$mes="编辑失败！<a href='listAdmin.php'>重新修改</a>";
}
return $mes;
}
function delAdmin($id){
if(delete("imooc_admin","id={$id}")){
$mes="删除成功!<br/><a href='listAdmin.php'>查看管理员列表</a>";
}else{
$mes="删除失败!<br/><a href='listAdmin.php'>请重新删除</a>";
}
return $mes;
}
