Re: MathCommentAuthenticator hanging Firefox on large weblog pages

[Oscar del Rio]

I wrote:

Looking at the javascript source, I thought it could be related to

clientSideInclude('commentAuthenticator','/roller/CommentAuthenticatorServlet');

defined in roller/theme/scripts/clientSideInclude.js, and the synchronous
XMLHttpRequest call

// Synchronous request, wait till we have it all
   req.open('GET', url, false);

(which according to http://jira.magnolia.info/browse/MAGNOLIA-283 could hang the browser if used in sync mode)

Update on my own post, again  :-)
Based on information found on other websites discouraging use of
synchronous XMLHttpRequest
http://developer.apple.com/internet/webcontent/xmlhttpreq.html

I made the following changes to roller/theme/scripts/clientSideInclude.js
to use asynchronous XMLHttpRequest with a callback function and the problem
seems to be fixed.  I don't know if it is the "correct" fix (I am
not familiar with XML/JavaScript) but it might help others with more 
experience...


// roller/theme/scripts/clientSideInclude.js

// global vars for access from callback function
var req = false;
var element;

function clientSideInclude(id, url) {
  // For Safari, Firefox, and other non-MS browsers
  if (window.XMLHttpRequest) {
    try {
      req = new XMLHttpRequest();
    } catch (e) {
      req = false;
    }
  } else if (window.ActiveXObject) {
    // For Internet Explorer on Windows
    try {
      req = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
      try {
        req = new ActiveXObject("Microsoft.XMLHTTP");
      } catch (e) {
        req = false;
      }
    }
  }
 // var element = document.getElementById(id);
 element = document.getElementById(id);
 if (!element) {
  alert("Bad id " + id +
   "passed to clientSideInclude." +
   "You need a div or span element " +
   "with this id in your page.");
  return;
 }
  if (req) {
    // Asynchronous request using processReqChange callback
    req.onreadystatechange = processReqChange;
//  req.open('GET', url, false);
    req.open('GET', url, true);
    req.send(null);
//  element.innerHTML = req.responseText;
//  } else {
//    element.innerHTML =
//   "Sorry, your browser does not support " +
//      "XMLHTTPRequest objects. This page requires " +
//      "Internet Explorer 5 or better for Windows, " +
//      "or Firefox for any system, or Safari. Other " +
//      "compatible browsers may also exist.";
  }
}


// handle onreadystatechange event of req object
function processReqChange() {
    // only if req shows "loaded"
    if (req.readyState == 4) {
        // only if "OK"
        if (req.status == 200) {
            element.innerHTML = req.responseText;
         } else {
            alert("There was a problem retrieving the XML data:\n" +
                req.statusText);
         }
    }
}