Question

请高手解释下，这段js，谢谢！

function ActiveTab(_tab, _content, isAjax, eventType){
this.tabs = [];
this.tabs_lis = [];
this.contents = [];
this.tabsDiv = document.getElementById(_tab);
this.contDiv = document.getElementById(_content);
this.last = -1;
this.isAjax = isAjax || false;
this.eventType = eventType || "click";
this.init(_tab, _content);
this.timer;
}

ActiveTab.prototype = {
addEvent: function(){
var tabs = this.tabs;
for(var i=0; i<tabs.length; i++){
tabs[i].flag = i;
tabs[i].self = this;
switch(this.eventType){
case "click":
tabs[i].onclick = function(){
this.self.shiftContent(this.flag);
return false;
}
break;
case "mouseover":
tabs[i].onmouseover = function(){
this.self.shiftContent(this.flag);
return false;
}
tabs[i].onclick = function(){
return false;
}
break;
}
}
},

shiftContent: function(current){
if(this.last >=0){
this.tabs_lis[this.last].className = "";
this.contents[this.last].style.display = "none";
}
this.tabs_lis[current].className = "on";
this.contents[current].style.display = "block";
if(this.isAjax){
Ajax.hiddenLoading();
this.callContent(this.tabs[current].href, this.contents[current]);
}
this.last = current;

},

callContent: function(_url, _targetNode){
var xhr = Ajax.createXHR();
xhr.open("GET", _url, true);
xhr.onreadystatechange = function(){
if(xhr.readyState == 1){
Ajax.showLoading();
}
if(xhr.readyState == 4){
if(xhr.status == 200){
_targetNode.innerHTML = xhr.responseText;
Ajax.hiddenLoading();
}
}
};
xhr.send(null);
},

init: function(_tab, _content){
this.tabs = this.tabsDiv.getElementsByTagName("A");
this.tabs_lis = this.tabsDiv.getElementsByTagName("li");
var elems = this.contDiv.childNodes;
for(var i=0; i<elems.length; i++){
if(elems[i].nodeType == 1){
elems[i].style.display = "none";
this.contents.push(elems[i]);
}
}
this.addEvent();
this.shiftContent(0);
},

autoActive: function(_time){
var self = this;
this.start(_time);
this.tabsDiv.onmouseover = this.contDiv.onmouseover = function(){
self.stop();
}
this.tabsDiv.onmouseout = this.contDiv.onmouseout = function(){
self.start(_time);
}
},
start: function(_time){
var self = this;
this.timer = setInterval(function(){
var current = self.last + 1;
if(current >= self.tabs.length) current = 0;
self.shiftContent(current);
}, _time);
},
stop: function(){
clearInterval(this.timer);
}
}
侧重js结构，我看过很多js都这样写的，请问什么意思呢？从ActiveTab.prototype 开始就有点糊涂了。。

Answer 1

对象.prototype.方法名=function(){} 这种结构是给JS对象添加内部元素

同时添加多个，变相的写法：
对象.prototype={
方法名:function(){},
方法名:function(){},
...
}
举例：
对象:
function node(id){
this.id=id;
this.name;
}
为对象添加方法:
node.prototype={
init:function(name){
this.name = name;
}
destroy:function(){
this.id=undefined;
this.name=undefined;
}
}
///调用
window.onload = function(){
var node = new node("id");
alert(node.id);
node.init("name");
alert(node.name);
node.destroy();
alert(node.id);
}

Answer 2

ActiveTab.prototype

这个你明白吗？？property这个类似于集成，这样添加的方法，在ActiveTab的实例中（就是new出来的对象）都会有该方法。
ActiveTab.prototype = {
addEvent: function(){
给ActiveTab类添加事件，然后是分支。这个写法相当于ActiveTab.prototype.addEvent=function(){
}只不过他写的时候把这些property方法都给包含进来了

给每一个table添加click mouseover等事件，事件的响应函数在下面。
有问题可以继续Hi我！
这是一个ajax的下拉菜单吧！