Bug 23933

Summary: XMLHttpRequest does not send/recieve data when executed following a Submit button click that triggers server-side behavior. When an functional XMLHttpRequest is being executed in a loop (successfully), and a Submit button is clicked that posts to the server (such as with a server task that takes a very long time to execute), the XMLHttpRequest immediately stops working, even while the loop continues to be executed. For instance, this code... xhr.onreadystatechange = function(){xhrCatch();} xhr.open("GET",strURL,true); xhr.send(null); ...works perfectly in any loop until a submit button is clicked. After the submit button is clicked, each loop will return an exception for xhr.readyState or xhr.status (as if they were null/undefined). Likewise, xhr.responseText and xhr.responseXML will also be null... as if the request was either not sent or not received. However, the function xhrCatch() triggered by xhr.onreadystatechange will still be executed ONCE after the button click... but still with the invalid values for responseText, readyState, etc. This was discovered when attempting to create an Ajax progress bar for a long-executing task triggered when a Submit button is clicked. The server writes to an XML file during each loop while AJAX reads from the XML file and displays the results on the page. Both the server action and the Ajax are triggered onclick. The progress bar is updated constantly until the task finishes and the page is redirected (server redirect). HOWEVER, even if the XMLHttpRequest loop is started on the page load, it will work absolutely correctly (even if the XML is updated by hand) UNTIL the button is clicked, at which point it immediately stops working and returns null/undefined xhr properties. I've been able to duplicate this on both Windows and OSX versions of Safari (3.2) as well as Chrome (1.0.154.48), using a number of different combinations of code event handlers and buttons. Firefox, Opera, and IE work perfectly both before and after the Submit button is clicked... while with Safari and Chrome the XMLHttpRequest always stops functioning immediately after a Submit button is clicked.