Why does jQuery insist my plain text is not "well-formed"?

Question

I'm making an AJAX call to retrieve some plain text:

$.ajax({
  url:         "programData.txt",
  type:        "GET",
  dataType:    "text",
  cache:       false,
  success:     processData
});

When I make the request, though, I get the following error:

Error: not well-formed Source File: file:///projects/foo/programData.txt?_=1259694590361 Line: 1, Column: 2

Why is jQuery trying to process my plain text and how do I get it to stop?

Answer 1

Supported types are:

* "xml": Treat the response as an XML document that can be processed via jQuery. 
* "html": Treat the response as HTML (plain text); included script tags are evaluated. 
* "script": Evaluates the response as JavaScript and evaluates it. 
* "json": Evaluates the response as JSON and sends a JavaScript Object to the success callback.

Perhaps use should use "html" instead of "text" since jQuery seems to not parse anything if you specify html as the type.

Answer 2

Are you loading up the page in your browser over HTTP or just opening it as a regular file? Does the address of the page running the javascript begin with http: or file: ? I suspect it is the latter, and Ajax calls work differently in that situation (see response by tvanfonsson below). If you're building a web app that will be served over HTTP later, try running your page using a local HTTP server.

Answer 3

You get different response codes when opening a local file via XMLHttpRequest than you do when using an HTTP request. I suspect that since you are opening a a local file, jQuery is choking on the response code, thinking it's an error because it's not 200 OK.

Reference

Example: Non-HTTP synchronous request

Despite its name, XMLHttpRequest can be used for non-HTTP requests. This example shows how to use it to fetch a file from the local file system.

var req = new XMLHttpRequest();
req.open('GET', 'file:///home/user/file.json', false); 
req.send(null);
if(req.status == 0)
  dump(req.responseText);

The key thing to note here is that the result status is being compared to 0 for success instead of 200. This is because the file and ftp schemes do not use HTTP result codes

Answer 4

jQuery doesn't seem to have this issue on chrome and ie8.