偶遇跨域怎么解决

直接上代码

在后台写 允许跨域的域名，

$allowedDomains = array("https://example1.com", "https://example2.com");

$origin = isset($_SERVER['HTTP_ORIGIN']) ? $_SERVER['HTTP_ORIGIN'] : '';

if (in_array($origin, $allowedDomains)) {
    header("Access-Control-Allow-Origin: " . $origin);
} else {
    header("HTTP/1.1 403 Forbidden");
    die("Access denied");
}

完全解决跨域问题，允许一切请求

header("Access-Control-Allow-Origin: *");

上代码

<?php

 
namespace app\api\controller;
use think\Db;
use think\Session;
use think\Controller;

header("Access-Control-Allow-Origin:*");
header("Access-Control-Allow-Headers:Origin,X-Requested-With,Content-Type,Accept");

class Index extends Controller
{
 
 
    public function index()
    {
       var_dump(11);die;
    }
    
    public function reg()
    {
       var_dump($_REQUEST);die;
    }
  
}

如果是 thinkphp框架，在public/index.php文件里面 namespace think;下面些

//允许跨域
// === CORS（支持凭证）开始 ===
$origin = $_SERVER['HTTP_ORIGIN'] ?? '';
// 允许的前端域名白名单（按你实际前端域名填写）
$allowOrigins = [
 
    'http://localhost:1617',   // 本地调试可选
];

 
if ($origin && in_array($origin, $allowOrigins, true)) {
    header("Access-Control-Allow-Origin: $origin");
    header("Access-Control-Allow-Credentials: true");
    header("Access-Control-Allow-Methods: GET,POST,PUT,DELETE,PATCH,OPTIONS");
    header("Access-Control-Allow-Headers: DNT,Keep-Alive,User-Agent,Cache-Control,Content-Type,Authorization,X-Requested-With,Platform,token");
    header("Vary: Origin"); // 让代理/缓存按来源区分
}

// 预检请求直接放行并返回 204（必须带上相同的 CORS 头）
if (strtoupper($_SERVER['REQUEST_METHOD'] ?? '') === 'OPTIONS') {
    http_response_code(204);
    header("Content-Length: 0");
    exit();
}
// === CORS 结束 ===


//end