Question

I have an HTML page with a JavaScript code that sends AJAX request. The request is being handled by my servlet. I’ve thought that it’s “better” and “more correct” to return the data as “application/json” MIME type from the servlet (response content type). However, it drives MSIE crazy – meaning the browser seems not to be capable to display/process this MIME type (Chrome/FF are just fine). When I specify no type explicitly – it works fine in all browsers. Is it real that no MIME type should be returned from servlet for AJAX requests?

Update: my server side is implemented in Java and the MIME type is being defined by a following line:

response.setContentType("application/json");

the response is the following text (only an example):

{ "status" : "DONE", "progress" : 100, "url" : "/7909118672283641787.docx" , "totalBytes" : 17696 } 

Update2: the snippet made of my client-side code (plain javascript, no libraries)

function display_progress(http) {
    if (http.readyState == 4) {
        var again = false;

        if (http.status != 200) {
            document.getElementById('progress_bar').innerHTML = "Wrong response status received: " + http.status + "! Fix the server-side code.";
        } else {
            try {
                var resp = eval('(' + http.responseText + ')');             
                var status = resp['status'];

                if (status == 'DOING') {
                    document.getElementById('progress_bar').innerHTML = "Uploaded: " + resp['progress'] + "%";
                    again = true;
                } else if (status == 'DONE'){
                    document.getElementById('progress_bar').innerHTML = 
                        "Uploaded 100% (" + resp['totalBytes'] + " bytes)! Your file is <a href=\"" + resp['url'] + "\"/>" + "here" + "</a>";
                } else if (status == 'ERROR') {
                    document.getElementById('progress_bar').innerHTML = "Error while uploading!";
                } else {
                    document.getElementById('progress_bar').innerHTML = "Unexpected state: " + status + "! Fix the server-side code.";
                }
            } catch (ex) {
                document.getElementById('progress_bar').innerHTML = "Wrong response received: " + resp + "! Fix the server-side code.";
            }
        }

        if (again) {
            setTimeout("update_progress()", 500);
        }
    }

Answer 1

As explained here: http://www.entwicklungsgedanken.de/2008/06/06/problems-with-internet-explorer-and-applicationjson/ text/javascript is the correct workaround.