请求标头字段Access-Control-Allow-Headers在预检响应中不允许使用Access-Control-Allow-Headers

Question

我试图从跨域创建一个登录页面,但我无法解决问题,错误是:

XMLHttpRequest无法加载http://localhost/testing/resp.php.请求标头字段Access-Control-Allow-Headers在预检响应中不允许使用Access-Control-Allow-Headers.

我的Javascript代码是:

$('#login').click(function(){
		var username = $('#uname').val();
		var password = $('#pass').val();
		var result = $('.result');
		result.text('loading....');

		if (username != '' && password !=''){
			var urltopass = 'action=login&username='+username+'&password='+password;
			$.ajax({
				type: 'POST',
				data: urltopass,
				headers: {"Access-Control-Allow-Headers": "Content-Type"},
				url: 'http://localhost/testing/resp.php',
				crossDomain: true,
				cache: false,
				success: function(responseText){
					console.log(responseText);
					if(responseText== "0"){
						result.text('incorrect login information');
					} else if (responseText == "1"){
						window.location="http://localhost/testing/home.php";
					} else{
						alert('error in sql query \n' + responseText);
					}
				}
			});
		} else return false;
	});

http://localhost/testing/resp.php的PHP代码:

<?php
	include "db.php"; //Connecting to database

	if (!isset($_SERVER['HTTP_ORIGIN'])) {
		echo "This is not cross-domain request";
    exit;
}
	header("Access-Control-Allow-Origin: *");
	header("Access-Control-Allow-Credentials: true");
	header("Access-Control-Allow-Methods: POST, GET, OPTIONS");
	header("Access-Control-Allow-Headers: Content-Type, Authorization, X-Requested-With");
	header('P3P: CP="CAO PSA OUR"'); // Makes IE to support cookies
	header("Content-Type: application/json; charset=utf-8");

	if (isset($_POST['action']) && $_POST['action'] == 'login'){
		$uname = $_POST['username'];
		$pass = $_POST['password'];

		$sql = "SELECT * FROM loginajax WHERE username='$uname' AND password='$pass'";
	
		$rs=$conn->query($sql);

		if (mysqli_num_rows($rs) <= 0){
			echo "0";
		} else {
			echo "1";
		}
		
	} else echo "this is not Login";

?>

Answer 1

删除这个:

headers: {"Access-Control-Allow-Headers": "Content-Type"},

来自你的jQuery.ajax调用.

服务器使用Access-Control-Allow-Headers标头响应,客户端不会将其发送到服务器.

客户端发送一个Access-Control-Request-Headers允许某些标头的请求,服务器以一个Access-Control-Allow-Headers列出其允许的实际标头的响应.客户端无法要求允许哪些标头.