During the Ext.ajax.request:ajax call, never overwrite the request.

The mistake of a day's adjustment today, very depressed, until the evening found that the original page is defined in the XMLHttpRequest object is a global object, but there are two Ajax calls to it, every few minutes there will be problems, or inexplicable problems, I think there is a problem of data parsing or background problems, Tune, the result is two Ajax calls, the second call the same request, that is, covering the first, the first time to get a second value, resulting in parsing error ....
Each subsequent Ajax call must not save the request with a global variable. Instead, it is generated temporarily and then binds the request to its processing.
function Test () {
var temp_request = Createxmlhttprequest ();
Deal_change.request = Temp_request;
Temp_request.onreadystatechange=deal_change;
Temp_request.open ("Get", url,true);
Temp_request.setrequestheader ("If-modified-since", "0"); Do not cache Ajax
Temp_request.send (NULL);
}
function Deal_change ()
{
var rstr;
try{
if (deal_change.request.readystate==4) \
Calling its request through a deal_change.request reference
{
if (deal_change.request.status==200)
{
RSTR = Trim (deal_change.request.responseText);
...................
}}}
Remember to remember.
Of course, if you use the framework, you don't have to bother. This article links http://www.cxybl.com/html/wyzz/JavaScript_Ajax/20120721/32053.html