Ajax在登录页面上提交

Question

我是PHP的新手。我正在尝试使用PHP和Ajax到logging将项目编码到另一个页面。但是在Ajax query中，某些部分没有执行，这意味着它会检查Ajax query部分中的所有内容，但是只要成功，它们就会在"Wrong combination"中始终显示alert。

这是我尝试过的代码：

登录页面HTML为：

form method="POST" class="form-signin">
                        <div class="account-logo">
                            <img src="assets/img/logo-dark.png" alt="">
                        </div>
                        <div class="form-group">
                            <label> Email</label>
                            <input type="email" name="email" id="email" autofocus="" class="form-control">
                        </div>
                        <div class="form-group">
                            <label>Password</label>
                            <input type="password" name="password" id="password" class="form-control">
                        </div>
                        <div class="form-group text-right">
                            <a href="forgot-password.html">Forgot your password?</a>
                        </div>
                        <div class="form-group text-center">
                            <input type="button" onClick="sendContact();" class="btn btn-primary account-btn" name="login" value="DO LOGIN" id="login_button">
                            <!-- <button type="submit" class="btn btn-primary account-btn">Login</button> -->
                        </div>
                        <div class="text-center register-link">
                            Don’t have an account? <a href="register.html">Register Now</a>
                        </div>
                    </form>

Ajax部分为：

function sendContact() {


    var email = $('#email').val();
    var password = $('#password').val();

    var data = {

        "email": email,
        "password": password,

    };

    jQuery.ajax({
        data: data,
        url: "auth/log.php", // Url to which the request is send
        type: "POST", // Type of request to be send, called as method

        success: function(data)
{
if(data==='success'){

    window.location.replace('index.php');
}
else{
alert('Wrong combination');

}

}

    });
    //  window.location.replace('index.php');


}

log.php页面将是

<?php

include "dbconnection.php";
session_start();

// $email=$_POST['email'];
// $password=$_POST['password'];

$select_data="select * from users where email='". $_POST['email']."' and password='".$_POST['password']."'";
$results= $conn->query($select_data);

if($results->num_rows>0){

$_SESSION["loggedin"] = true;
$_SESSION["user"] = $email;


echo 'success';


}else{
    echo 'fail';

}

?>

这里有人可以帮我吗