Fixes #12518, removes an offsetWidth on focus/blur events for an <IE9 bug that...

Fixes #12518, removes an offsetWidth on focus/blur events for an <IE9 bug that caused a performance hit. Closes gh-958

src/event.js

@@ -327,8 +327,7 @@ jQuery.event = {
 				// Call a native DOM method on the target with the same name name as the event.
 				// Can't use an .isFunction() check here because IE6/7 fails that test.
 				// Don't do default actions on window, that's where global variables be (#6170)
-				// IE<9 dies on focus/blur to hidden element (#1486)
-				if ( ontype && elem[ type ] && ((type !== "focus" && type !== "blur") || event.target.offsetWidth !== 0) && !jQuery.isWindow( elem ) ) {
+				if ( ontype && elem[ type ] && !jQuery.isWindow( elem ) ) {
 
 					// Don't re-trigger an onFOO event when we call its FOO() method
 					old = elem[ ontype ];
@@ -339,7 +338,12 @@ jQuery.event = {
 
 					// Prevent re-triggering of the same event, since we already bubbled it above
 					jQuery.event.triggered = type;
-					elem[ type ]();
+					try {
+						elem[ type ]();
+					} catch ( e ) {
+						// IE<9 dies on focus/blur to hidden element (#1486,#12518)
+						// only reproducible on winXP IE8 native, not IE9 in IE8 mode
+					}
 					jQuery.event.triggered = undefined;
 
 					if ( old ) {