Create and throw away IFRAME to make back button work.

At least now the back button won't trigger the drop-down notification.

war/src/main/webapp/scripts/hudson-behavior.js

@@ -589,7 +589,8 @@ var jenkinsRules = {
     },
 
     "INPUT.applyButton":function (e) {
-        var id = "iframe"+(iota++);
+        var id;
+        var containerId = "container"+(iota++);
 
         var responseDialog = new YAHOO.widget.Panel("wait"+(iota++), {
             fixedcenter:true,
@@ -601,9 +602,9 @@ var jenkinsRules = {
         });
 
         responseDialog.setHeader("Error");
-        responseDialog.setBody("<iframe id='"+id+"' name='"+id+"' style='height:100%; width:100%'></iframe>");
+        responseDialog.setBody("<div id='"+containerId+"'></iframe>");
         responseDialog.render(document.body);
-        var target = $(id); // iframe
+        var target; // iframe
 
         function attachIframeOnload(target, f) {
             if (target.attachEvent) {
@@ -613,26 +614,33 @@ var jenkinsRules = {
             }
         }
 
-        var attached = false;
         makeButton(e,function (e) {
             var f = findAncestor(e.target, "FORM");
 
-            if (!attached) {
-                attached = true;
-                attachIframeOnload(target, function () {
-                    if (target.contentWindow && target.contentWindow.applyCompletionHandler) {
-                        // apply-aware server is expected to set this handler
-                        target.contentWindow.applyCompletionHandler(window);
-                    } else {
-                        // otherwise this is possibly an error from the server, so we need to render the whole content.
-                        var r = YAHOO.util.Dom.getClientRegion();
-                        responseDialog.cfg.setProperty("width",r.width*3/4+"px");
-                        responseDialog.cfg.setProperty("height",r.height*3/4+"px");
-                        responseDialog.center();
-                        responseDialog.show();
-                    }
-                });
-            }
+            // create a throw-away IFRAME to avoid back button from loading the POST result back
+            id = "iframe"+(iota++);
+            target = document.createElement("iframe");
+            target.setAttribute("id",id);
+            target.setAttribute("name",id);
+            target.setAttribute("style","height:100%; width:100%");
+            $(containerId).appendChild(target);
+
+            attachIframeOnload(target, function () {
+                if (target.contentWindow && target.contentWindow.applyCompletionHandler) {
+                    // apply-aware server is expected to set this handler
+                    target.contentWindow.applyCompletionHandler(window);
+                } else {
+                    // otherwise this is possibly an error from the server, so we need to render the whole content.
+                    var r = YAHOO.util.Dom.getClientRegion();
+                    responseDialog.cfg.setProperty("width",r.width*3/4+"px");
+                    responseDialog.cfg.setProperty("height",r.height*3/4+"px");
+                    responseDialog.center();
+                    responseDialog.show();
+                }
+                window.setTimeout(function() {// otherwise Firefox will fail to leave the "connecting" state
+                    $(id).remove();
+                },0)
+            });
 
             f.target = target.id;
             f.elements['core:apply'].value = "true";