网页无法自动跳转，代码如下，跪求大神回答！！！！！
<title>用户验证</title>
<?php
session_start();
$user=trim($_POST['user']);
$pass=trim($_POST['pass']);
if($user=="admin"&&$pass="admin"){
echo "登录成功";
$_SESSION['user']=$user;
$_SESSION['pass']=$pass;
$_SESSION['producelist']="";
$_SESSION['quatity']="" ; //初始化购物车内没有商品
echo "<meta http-equiv=\"refresh\" conten=\"3;url=books.php\">3秒转入主页，wait";//此行代码为什么不能自动跳转到books.php
}else{
echo "<script>alert('登录失败');history.back();</script>";
}
?>
