Makes sure no unload handler is bound when not in IE. Also simplifies the whole ...

diff --git a/src/ajax/xhr.js b/src/ajax/xhr.js
index 5dbc33d3fd7e7751a1ea15628993f2f2ac1c63d8..a87c323927b3e7d172ccbfa81a31a465aa81bc17 100644 (file)
--- a/src/ajax/xhr.js
+++ b/src/ajax/xhr.js
@@ -1,21 +1,14 @@
 (function( jQuery ) {
 
-var // #5280: next active xhr id and list of active xhrs' callbacks
-       xhrId = jQuery.now(),
-       xhrCallbacks,
-
-       // XHR used to determine supports properties
-       testXHR;
-
-// #5280: Internet Explorer will keep connections alive if we don't abort on unload
-function xhrOnUnloadAbort() {
-       jQuery( window ).unload(function() {
+var // #5280: Internet Explorer will keep connections alive if we don't abort on unload
+       xhrOnUnloadAbort = window.ActiveXObject ? function() {
                // Abort all pending requests
                for ( var key in xhrCallbacks ) {
                        xhrCallbacks[ key ]( 0, 1 );
                }
-       });
-}
+       } : false,
+       xhrId = 0,
+       xhrCallbacks;
 
 // Functions to create xhrs
 function createStandardXHR() {
@@ -45,15 +38,13 @@ jQuery.ajaxSettings.xhr = window.ActiveXObject ?
        // For all other browsers, use the standard XMLHttpRequest object
        createStandardXHR;
 
-// Test if we can create an xhr object
-testXHR = jQuery.ajaxSettings.xhr();
-jQuery.support.ajax = !!testXHR;
-
-// Does this browser support crossDomain XHR requests
-jQuery.support.cors = testXHR && ( "withCredentials" in testXHR );
-
-// No need for the temporary xhr anymore
-testXHR = undefined;
+// Determine support properties
+(function( xhr ) {
+       jQuery.extend( jQuery.support, {
+               ajax: !!xhr,
+               cors: !!xhr && ( "withCredentials" in xhr )
+       });
+})( jQuery.ajaxSettings.xhr() );
 
 // Create transport if the browser can provide an xhr
 if ( jQuery.support.ajax ) {
@@ -136,7 +127,9 @@ if ( jQuery.support.ajax ) {
                                                                // Do not keep as active anymore
                                                                if ( handle ) {
                                                                        xhr.onreadystatechange = jQuery.noop;
-                                                                       delete xhrCallbacks[ handle ];
+                                                                       if ( xhrOnUnloadAbort ) {
+                                                                               delete xhrCallbacks[ handle ];
+                                                                       }
                                                                }
 
                                                                // If it's an abort
@@ -197,15 +190,18 @@ if ( jQuery.support.ajax ) {
                                        if ( !s.async || xhr.readyState === 4 ) {
                                                callback();
                                        } else {
-                                               // Create the active xhrs callbacks list if needed
-                                               // and attach the unload handler
-                                               if ( !xhrCallbacks ) {
-                                                       xhrCallbacks = {};
-                                                       xhrOnUnloadAbort();
+                                               handle = ++xhrId;
+                                               if ( xhrOnUnloadAbort ) {
+                                                       // Create the active xhrs callbacks list if needed
+                                                       // and attach the unload handler
+                                                       if ( !xhrCallbacks ) {
+                                                               xhrCallbacks = {};
+                                                               jQuery( window ).unload( xhrOnUnloadAbort );
+                                                       }
+                                                       // Add to list of active xhrs callbacks
+                                                       xhrCallbacks[ handle ] = callback;
                                                }
-                                               // Add to list of active xhrs callbacks
-                                               handle = xhrId++;
-                                               xhr.onreadystatechange = xhrCallbacks[ handle ] = callback;
+                                               xhr.onreadystatechange = callback;
                                        }
                                },