javascript AutoScroller function class_javascript skills

Copy code The code is as follows:

/*
* Copyright (C) 2007-2009 skylark
* Email:aohailin@gmail.com
* Version:2.1
* Original program, please retain copyright for reprinting
*/
var $=function(o){return typeof o==" string"?document.getElementById(o):o;};
function AutoScroll(){
this.obj=[];
this.version="2.1";
this.Build( );//Initialization
};
AutoScroll.prototype.Build=function(){
var me=this;
//Get other scroll events
var oldscroll=window.onscroll;
window.onscroll=function(){
//Protect other scroll events
if("function"==typeof oldscroll){
oldscroll();
}
// Get client browser parameters, compatible with IE, FF, Chrome
this.common={
t:document.documentElement.scrollTop||document.body.scrollTop,
h:document.documentElement.clientHeight| |document.body.clientHeight,
w:document.documentElement.clientWidth||document.body.clientWidth
};
this.position=[];
for(var i=0;i< ;me.obj.length;i ){
try{
this.style={};
//Get the client location and set 7 positions
//In order to minimize the automatic Adapt to the position. The position is dynamically calculated here, so when the scroll event is triggered, the CPU consumption is very large
this.position[i]=[
{x:0,y:this.common.t},
{ x:this.common.w-me.obj[i].obj.offsetWidth,y:this.common.t},
{x:0,y:(this.common.h this.common.t- me.obj[i].obj.offsetHeight)/2 (this.common.t)/2},
{x:this.common.w-me.obj[i].obj.offsetWidth,y:( this.common.h this.common.t-me.obj[i].obj.offsetHeight)/2 (this.common.t)/2},
{x:(this.common.w-me. obj[i].obj.offsetWidth)/2,y:(this.common.h this.common.t-me.obj[i].obj.offsetHeight)/2 (this.common.t)/2},
{x:0,y:this.common.h this.common.t-me.obj[i].obj.offsetHeight},
{x:this.common.w-me.obj[i ].obj.offsetWidth,y:this.common.h this.common.t-me.obj[i].obj.offsetHeight}
];
//Handling custom styles
this.style ="object"==typeof me.obj[i].style?{x:me.obj[i].style.left,y:me.obj[i].style.top this.common.t}:{ x:this.position[i][me.obj[i].style].x,y:this.position[i][me.obj[i].style].y};
//Position
me.obj[i].obj.style.left=this.style.x "px";
me.obj[i].obj.style.top=this.style.y "px";
}catch(e){
//The function is to filter invalid obj
for(var j=i;jme.obj[j] =me.obj[j 1];
me.obj.length=me.obj.length-1;
}
}
}
};
//Initialization
window.scroll(1,1);
};
AutoScroll.prototype.Add=function(){
var obj=arguments[0];
//Get the current position
var oldposition=$(obj.id).style.position;
$(obj.id).style.position="absolute";
//Do not use fixed, although higher version browsers already support it fixed
this.obj.push({
obj:$(obj.id),
oldposition:oldposition,
style:obj.style
});
};
AutoScroll.prototype.Remove=function(){
var obj=arguments[0];
for(var i=0;iif(this .obj[i].obj==$(obj.id)){
//Restore initial state position
this.obj[i].obj.style.position=this.obj[i].oldposition ;
//Whether to really remove
if(obj.remove){
this.obj[i].obj.innerHTML="";
document.body.removeChild(this.obj[ i].obj);
}
//Remove obj
for(var j=i;jthis.obj[j] =this.obj[j 1];
}
this.obj.length=this.obj.length-1;
break;
}
}
};
var Scroller=new AutoScroll();