XMLHttpRequest状态为0

Question

I am using window.XMLHttpRequest . The line commands are below.

The problem is that it is returning status = 0 . I checked the url but it is right. What am I doing wrong?

var url = "http://177.55.99.146:8080/autenticacao/autentica?arquivo=" + file; 
req.open("Get", url, true); 
req.send(null);

Answer 1

Most of the time this is caused by a cross-domain request (I assume your request is cross-domain since you specified the full url). Did you use the Access-Control-Allow-Origin header at http://177.55.99.146:8080/autenticacao/autentica ?

Like this:

<?php
    header("Access-Control-Allow-Origin: http://www.allowed-domain.com");
?>