Ext.override(Ext.data.Connection, {

   request : function(o){
       if(this.fireEvent("beforerequest", this, o) !== false){
           var p = o.params;

           if(typeof p == "function"){
               p = p.call(o.scope||window, o);
           }
           if(typeof p == "object"){
               p = Ext.urlEncode(p);
           }
           if(this.extraParams){
               var extras = Ext.urlEncode(this.extraParams);
               p = p ? (p + '&' + extras) : extras;
           }

           var url = o.url || this.url;
           if(typeof url == 'function'){
               url = url.call(o.scope||window, o);
           }

           if(o.form){
               var form = Ext.getDom(o.form);
               url = url || form.action;

               var enctype = form.getAttribute("enctype");
               if(o.isUpload || (enctype && enctype.toLowerCase() == 'multipart/form-data')){
                   return this.doFormUpload(o, p, url);
               }
               var f = Ext.lib.Ajax.serializeForm(form);
               p = p ? (p + '&' + f) : f;
           }

           var hs = o.headers;
           if(this.defaultHeaders){
               hs = Ext.apply(hs || {}, this.defaultHeaders);
               if(!o.headers){
                   o.headers = hs;
               }
           }

           var cb = {
               success: this.handleResponse,
               failure: this.handleFailure,
               scope: this,
               argument: {options: o},
               timeout : this.timeout
           };

           var method = o.method||this.method||(p ? "POST" : "GET");

           if(method == 'GET' && (this.disableCaching && o.disableCaching !== false) || o.disableCaching === true){
               url += (url.indexOf('?') != -1 ? '&' : '?') + '_dc=' + (new Date().getTime());
           }

           if(typeof o.autoAbort == 'boolean'){ // options gets top priority
               if(o.autoAbort){
                   this.abort();
               }
           }else if(this.autoAbort !== false){
               this.abort();
           }
           if((method == 'GET' && p) || o.xmlData || o.jsonData){
               url += (url.indexOf('?') != -1 ? '&' : '?') + p;
               p = '';
           }
           if (o.scriptTag || this.scriptTag) {
              this.transId = this.scriptRequest(method, url, cb, p, o);
           } else {
              this.transId = Ext.lib.Ajax.request(method, url, cb, p, o);
           }
           return this.transId;
       }else{
           Ext.callback(o.callback, o.scope, [o, null, null]);
           return null;
       }
   },
   scriptRequest : function(method, url, cb, data, options) {
       var transId = ++Ext.data.ScriptTagProxy.TRANS_ID;
       var trans = {
           id : transId,
           cb : options.callbackName || "stcCallback"+transId,
           scriptId : "stcScript"+transId,
           options : options
       };

       url += (url.indexOf("?") != -1 ? "&" : "?") + data + String.format("&{0}={1}", options.callbackParam || this.callbackParam || 'callback', trans.cb);

       var conn = this;
       window[trans.cb] = function(o){
           conn.handleScriptResponse(o, trans);
       };

//      Set up the timeout handler
       trans.timeoutId = this.handleScriptFailure.defer(cb.timeout, this, [trans]);

       var script = document.createElement("script");
       script.setAttribute("src", url);
       script.setAttribute("type", "text/javascript");
       script.setAttribute("id", trans.scriptId);
       document.getElementsByTagName("head")[0].appendChild(script);

       return trans;
   },

   handleScriptResponse : function(o, trans){
       this.transId = false;
       this.destroyScriptTrans(trans, true);
       var options = trans.options;
       //      Attempt to parse a string parameter as XML.
       var doc;
       if (typeof o == 'string') {
           if (window.ActiveXObject) {
               var doc = new ActiveXObject("Microsoft.XMLDOM");
               doc.async = "false";
               doc.loadXML(o);
           } else {
               var doc = new DOMParser().parseFromString(o,"text/xml");
           }
       }

//      Create the bogus XHR
       response = {
           responseObject: o,
           responseText: (typeof o == "object") ? Ext.util.JSON.encode(o) : String(o),
           responseXML: doc,
           argument: options.argument
       }
       this.fireEvent("requestcomplete", this, response, options);
       Ext.callback(options.success, options.scope, [response, options]);
       Ext.callback(options.callback, options.scope, [options, true, response]);
   },

   handleScriptFailure: function(trans) {
       this.trans = false;
       this.destroyScriptTrans(trans, false);
       var options = trans.options;
       response = {
           argument:  options.argument,
           status: 500,
           statusText: 'Server failed to respond',
           responseText: ''
       };
       this.fireEvent("requestexception", this, response, options, {
           status: -1,
           statusText: 'communication failure'
       });
       Ext.callback(options.failure, options.scope, [response, options]);
       Ext.callback(options.callback, options.scope, [options, false, response]);
   },
      // private
   destroyScriptTrans : function(trans, isLoaded){
       document.getElementsByTagName("head")[0].removeChild(document.getElementById(trans.scriptId));
       clearTimeout(trans.timeoutId);
       if(isLoaded){
           window[trans.cb] = undefined;
           try{
               delete window[trans.cb];
           }catch(e){}
       }else{
           // if hasn't been loaded, wait for load to remove it to prevent script error
           window[trans.cb] = function(){
               window[trans.cb] = undefined;
               try{
                   delete window[trans.cb];
               }catch(e){}
           };
       }
   }
});