Front-end performance optimization: Rewrite yourself, reduce judgment

Rewrite yourself how to reduce judgment? In fact, I also learn the code of others, just understand.

Specific code:

 Compatible binding event methods function AddHandler (target, EventType, handler) {//Override own if (target.addeventlist Ener) {//dom2 Events AddHandler = function (target, EventType, handler) {Target.addev                Entlistener (EventType, Handler, false);            }; } else {//ie AddHandler = function (target, EventType, handler) {target.attachevent ("                On "+ EventType, handler);            };        }//Key, call new method, rewrite yourself, reduce judgment, second call, use new method, no judgment AddHandler (target, EventType, handler); } function RemoveHandler (target, EventType, handler) {//o//overrides itself if (target.removeeventliste NER) {//dom2 Events removehandler = function (target, EventType, handler) {Target.add                EventListener (EventType, Handler, false);            }; } else {//ie RemoveHandler = function (target, EventType, handler){target.detachevent ("on" + EventType, handler);            };        }//Key, call new method, rewrite yourself, reduce judgment, second call, use new method, no judgment RemoveHandler (target, EventType, handler); }

The general person's writing is this:

function AddHandler (target, EventType, handler) {                      if (target.addeventlistener) {//dom2 Events                 Target.addeventlistener (EventType, Handler, false);            } else {//ie                 target.attachevent ("on" + EventType, handler);            }                   }

Although a few lines of code, but the idea is completely different, the average person writes, every time the binding must be judged, can be written only once judge!!! Only once!!!

Front-end performance optimization: Rewrite yourself, reduce judgment