正确取得transitionend事件的可用名字

transitionend_name.js

            function getTransitionEndEventName() {
                var obj = {
                    TransitionEvent: "transitionend",
                    WebKitTransitionEvent: "webkittransitionEnd",
                    OTransitionEvent: "OTransitionEnd",
                    otransitionEvent: "otransitionEnd",
                    MSTransitionEvent: "MSTransitionEnd"
                }
                //  var ev = document.createEvent("TransitionEvent"); // FIXME: un-specified
                //  ev.initTransitionEvent("transitionend", true, true, "some-unknown-prop", -4.75);
                //  document.body.dispatchEvent(ev);
                var ret = false, ev
                for (var name in obj) {
                    try {
                        ev = document.createEvent(name)//只有firefox不支持
                        ret = obj[name]
                        break
                    } catch (e) {
                    }
                }
                if (ret === false) {
                    //https://bugzilla.mozilla.org/show_bug.cgi?id=868751
                    //https://hg.mozilla.org/integration/mozilla-inbound/rev/a20ea0d494a0
                    try {
                        ev = new TransitionEvent("transitionend",
                                {
                                    bubbles: true,
                                    cancelable: true,
                                    propertyName: "some-unknown-prop",
                                    elapsedTime: 0.5,
                                    pseudoElement: "pseudo"
                                });
                        ret = "transitionend"
                    } catch (e) {
                    }
                }
                getTransitionEndEventName = function() {
                    return ret
                }
                return ret
            }
            console.log(getTransitionEndEventName() + "!!!!!!!!!!!!!!!!")