Question

I have a simple JavaScript function that opens an XML-File. The file URL is simply the one of the website displayed right now, obtained in the JavaScript file of a Firefox extension via

var url =content.document.location.href;

this works just fine, next,

xml=loadXMLDoc(url);

should give me this file, which works just fine on websites on the internet. however, I set up a local machine now, and instead of http:publicwebsite.com/file.rdf I now have http://localhost/file.rdf and suddenly the JavaScript function loadXMLDoc does not produce any result.

function loadXMLDoc(dname)

{

if (window.XMLHttpRequest)

{

    xhttp=new XMLHttpRequest();

}

else

{

    xhttp=new ActiveXObject("Microsoft.XMLHTTP");

}
try 
{
    xhttp.open("GET",dname,false); // open server interface
} 
catch (err)
{ // if error occurs
    alert("XMLHttpRequest.open() failed.\n"+    err);
}


xhttp.open("GET",dname,false);

xhttp.send("");
alert(xhttp.responseXML);

return xhttp.responseXML;

}

the alert(xhttp.responseXML); returns null.

Is this a problem with the same origin policy or what did I miss?

Answer 1

You are writing an extension – there is no same-origin policy, you are allowed to read whatever you like. I rather suspect that the MIME type returned by your local server is incorrect, it needs to be an XML MIME type to be processed by XMLHttpRequest correctly (probably application/rdf+xml in this case). If you are using Apache the following directive in the server config should do:

AddType application/rdf+xml .rdf

If you cannot influence the server but you are certain that what you get back is an XML file you can also use overrideMimeType:

xhttp.overrideMimeType("application/rdf+xml");