JavaScript gets event Object

Usually we get the event object generally written as follows: function GetEvent (event) {return Event | | window.event//IE:window.event}

If there are no arguments, it can be written (non ie: the event object is automatically passed to the corresponding event handler and the first argument):

function GetEvent () {
return arguments[0] window.event//IE:window.event
}

Such a way of writing in addition to Firefox (Beta version: 3.0.12, the same as the same) browser on the run will not be a problem, but Firefox why the exception? Let's take a situation like this:

button

Running results in Firefox is undefined, why?

In Firefox the call is actually like this, the first call to execute is:

function onclick (event) {
Foo ();
}

The call is then executed by:

function foo () {
var e = getEvent ();
Alert (e);
}

You will find that the Foo () in onclick= "foo ()" In Firefox cannot automatically pass in the event object parameters, and the default is passed to the system-generated onclick function, which we can pass through the getEvent.caller.caller.arguments [0] Gets the event object.

Therefore, our getEvent can be optimized (refer to the GetEvent method in the Event/event-debug.js in yui_2.7.0b):

function GetEvent (event) {
var ev = event window.event;
if (!ev) {
var c = This.getEvent.caller;
while (c) {
EV = C.arguments[0];
if (ev && (Event = = Ev.constructor MouseEvent = = Ev.constructor)) {/Yiwen Fei Note: YUI source bug,ev.constructor may also be Mouseeven T, not necessarily an Event
Break
}
c = C.caller;
}
}
return EV;
}

One simple solution, of course, is to manually pass parameters to onclick= "foo ()":

button