function getIframeContentJson(id, iframe) {
        /*jshint evil: true*/

        var response, doc, innerHtml;

        //IE may throw an "access is denied" error when attempting to access contentDocument on the iframe in some cases
        try {
            // iframe.contentWindow.document - for IE<7
            doc = iframe.contentDocument || iframe.contentWindow.document;
            innerHtml = doc.body.innerHTML;

            log("converting iframe's innerHTML to JSON");
            log("innerHTML = " + innerHtml);
            //plain text response may be wrapped in <pre> tag
            if (innerHtml && innerHtml.match(/^<pre/i)) {
                innerHtml = doc.body.firstChild.firstChild.nodeValue;
            }

            response = handler._parseJsonResponse(innerHtml);
        }
        catch (error) {
            log("Error when attempting to parse form upload response (" + error.message + ")", "error");
            response = {success: false};
        }

        return response;
    }
Returns json object received by iframe from server.