我目前库存：（基本上我正在做一个登录页面没有问题，但登录页面一旦我提交它。。。这是我登录页面的代码。

<form action= "process.php" method="POST">
Username: <input type="text" id="user" name="username">
Password: <input type="password" id="pass" name="password">
<input type="submit" value="Submit" >

但是现在我的process.php也犯了同样的错误。我似乎找不到问题所在。请帮忙这是密码

<?php
    $username = $_POST['user'];
    $password = $_POST['pass'];

    //to prevent sql injection
    $username = stripcslashes($username);
    $password = stripcslashes($password);
    $username = mysql_real_escape_string($username);
    $password = mysql_real_escape_string ($password);

    //connect to the server and select database
    mysql_connect("localhost","root","");
    mysql_select_db("franklin offshore");

    //query the database for user
    $result = mysql_query("select * from login where username='$username' 
    and password='$password'")
        or die ("Failed to query database ".mysql_error());
    $row = mysql_fetch_array($result);
    if ($row['username'] == $username && $row['password'] == $password)
    {
        echo "LOGIN SUCCESS WELCOME" .$row['username'];
    }
    else
    {
        echo "Failed to LOGIN" ;
    }
?>

这就是它一直在展示的东西
致命错误：未捕获错误：调用未定义函数mysql\u real\u escape\u string（）
请帮忙