Two things to say: A probe into the use of 1.this pointers. 2.ie Attachevent and Firefox addeventlistener differences in event handling _javascript skills

First thing.
This clock is a special finger clock in the JavaScript language that points to the current object that calls the this statement when the code is running.
If it is an event-bound function, it points to the bound element itself.
<script type= "Text/javascript" >
by Go_rush (Asun) from http://ashun.cnblogs.com/
Alert (This===window)//true Straight
When the call is received, point to window itself
var gorush={
F:function () {
Alert (This===gorush)//true
}
}
GORUSH.F ()//point to Gorush Object
Document.onclick=function () {
Alert (this===document)//true, pointing to document
}
/*
Element.onclick=function () {
Alert (this===element)//true
}
*/
</script>
Notably, when multiple objects are nested, this refers to the object that has recently called it.
obj1={
obj2:{
F:function () {
Alert (THIS===OBJ1.OBJ2)//Here This does not point to obj1 oh.
}
}
}
OBJ1.OBJ2.F ()
To give a very error-prone example, click here to see the relevant links
<script type= "Text/javascript" >
by Go_rush from http://ashun.cnblogs.com/
The use of this in the following gorush1 is wrong, this error 10 programmers 6 commit
var gorush1={
Showmsg:function () {alert ("Hello,world")},
Doajax:function () {
New Ajax.request ("index.php", {onsuccess:function () {
This.showmsg ()
}})
}
}
Gorush2 is right.
var gorush2={
Showmsg:function () {alert ("Hello,world")},
Doajax:function () {
var self=this; Backing up GORUSH2 objects
New Ajax.request ("index.php", {onsuccess:function () {
Self.showmsg ()
}})
}
}
</script>

Second thing:
Gossip is not much to say, first dish dishes.
<script type= "Text/javascript" >
var btn=null
Window.onload=function () {
Btn=document.getelementbyid ("BTN")
if (window.attachevent) btn.attachevent ("onclick", Gorush);
if (Window.addeventlistener) Btn.addeventlistener ("click", Gorush,false)
}
function Gorush () {
if (This===window) alert ("This==window")//ie6.0, this sentence will execute
if (THIS===BTN) alert ("This==btn")//ff1.5, this sentence will execute
}
</script>
<input type= "button" value= "click Me" id= "btn" >
I really do not understand why IE will do so, people are very depressed ah, why this point to the window?
Workaround:
1. When the event is bound don't use attachevent, poor me, that was the Prototype.js Event.observe method
So element.onclick=function ... So in two browsers this means the clock points to element
2. Use the GetEvent () method to get the event uniformly in the processing function Gorush, and then use Evt.srcelement | | Evt.target Get the Element object