ionic2/angular2 cannot access the api created by laravel5.3

laravel 5.3 api has been configured

<code>    //category.service.ts
    private headers = new Headers({'Content-Type': 'application/json','Accept':'application/json','Authorization':'Bearer '+window.localStorage.getItem('token')});

    private heroesUrl = 'http://xingao.5188cms.com/api/user';  // URL to web api

    private handleError(error: any): Promise<any> {
      console.error('An error occurred', error); // for demo purposes only
      return Promise.reject(error.message || error);
    }
</code>

Access like this, promptXMLHttpRequest cannot load http://xingao.5188cms.com/api/user. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8100' is therefore not allowed access., it seems to be a cross-domain problem, but I can successfully obtain the data using postman

Step 2

I changed the link to onehttp://xingao.5188cms.com/test.php

<code>//test.php
<?php 
header("Access-Control-Allow-Origin: *");
$arr=['1','2'];

echo json_encode($arr);
?></code>

Still not workingXMLHttpRequest cannot load http://xingao.5188cms.com/test.php. Request header field authorization is not allowed by Access-Control-Allow-Headers in preflight response.

Step 3

I changed the link to /test.json, but it works

Then what is the reason? . . .

Reply content:

laravel 5.3 api has been configured

<code>    //category.service.ts
    private headers = new Headers({'Content-Type': 'application/json','Accept':'application/json','Authorization':'Bearer '+window.localStorage.getItem('token')});

    private heroesUrl = 'http://xingao.5188cms.com/api/user';  // URL to web api

    private handleError(error: any): Promise<any> {
      console.error('An error occurred', error); // for demo purposes only
      return Promise.reject(error.message || error);
    }
</code>

Access like this, promptXMLHttpRequest cannot load http://xingao.5188cms.com/api/user. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:8100' is therefore not allowed access., it seems to be a cross-domain problem, but I can successfully obtain the data using postman

Step 2

I changed the link to onehttp://xingao.5188cms.com/test.php

<code>//test.php
<?php 
header("Access-Control-Allow-Origin: *");
$arr=['1','2'];

echo json_encode($arr);
?></code>

Still not workingXMLHttpRequest cannot load http://xingao.5188cms.com/test.php. Request header field authorization is not allowed by Access-Control-Allow-Headers in preflight response.

Step 3

I changed the link to /test.json, but it works

Then what is the reason? . . .

Access-Control-Allow-Origin
Cross-domain problem
This is a browser limitation