无法通过xmlhttprequest加载本地xml文件

Question

I am using XAMPP Apache on port 80.

When I try with localhost in the url I get:

XMLHttpRequest cannot load http://localhost/ice_escape/pokus.xml . Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access.

and also:

Uncaught TypeError: Cannot read property '0' of null

I tried allowing CORS by adding this to httpd.conf to no avail:

Header always set Access-Control-Allow-Origin "*"
Header always set Access-Control-Max-Age "1000"
Header always set Access-Control-Allow-Headers "X-Requested-With, Content-Type, Origin, Authorization, Accept, Client-Security-Token, Accept-Encoding"
Header always set Access-Control-Allow-Methods "POST, GET, OPTIONS, DELETE, PUT"

Then I tried changing localhost to 127.0.0.1 . It removes the first error, but the other error persists.

var url = "http://127.0.0.1/iceescape/pokus.xml";
var xmlhttp;
if (window.XMLHttpRequest) {
      xmlhttp = new XMLHttpRequest();
}

if (xmlhttp) {

    xmlhttp.open("GET", url, true);
    xmlhttp.setRequestHeader('Content-Type', 'text/xml');
    xmlhttp.onreadystatechange = function () {
        if (xmlhttp.readyState == 4) {
            txt = xmlhttp.responseText;
            {//---- some code that parses the xml
                 var strWidth = "width";
                 var a = txt.indexOf(strWidth);
                 a += strWidth.length;
                 txt = txt.slice(a,(txt.length) );
                 var width = txt.match(/\d+/)[0];// here it says its null                    
                }
             } 
        }
    };
    xmlhttp.send();

the xml:

<?xml version="1.0" encoding="UTF-8"?>
<map width = "2400" height = "1800">
    <ghost type="troll" speed="5">
        <point>
        {100,200}
        </point>
        <point>
        {350,250}
        </point>
    </ghost>

Answer 1

What you are trying to read with XHR is not a local file.

You have origin null (which means your HTML document is a local file , loaded via the file:// URL scheme) and you are making the Ajax result to http://localhost/ice_escape/pokus.xml which is an HTTP resource on the same computer.

Load your HTML document from the web server too.