自己编写的ajax类_javascript
前些天，自己特别忠于对javascript的学习，看到网上出色的javascript AJAX应用，于是变萌发了编写一个属于自己的Ajax类的想法。
代码还有很多不足，希望各位大侠们帮忙之处，小弟在这不慎感激！
此类还在不断优化中。。。呵呵
说明：
- 提供Ajax.get()发送请求
- 提供Ajax.post()发送请求
- 内部绑定定时函数来执行循环发送请求
- 合理处理空闲请求
/*
* Ajax-lib.js
* {by}d.n.sky
* {website}desetang.com
* {description}Ajax类
*/
var Ajax = function(){};
/* 创建请求基础类 */
Ajax.prototype = {
/* 重新发送请求时间（请求未完成） */
retryDelay: 5,
/* 是否对未完成的队列进行定时处理 */
isDisp: false,
/* 缓存对象 */
cacheXMLHttp: [],
/* 二维数组储存(记录请求中text/html/xml的最后修改时间) */
lastModified: [],
/* 返回xmlhttp对象 */
getFreeXMLHttp: function(){
/* 从对象池中获取空闲请求 */
for(var i = 0, len = this.cacheXMLHttp.length; i < len; i++){
var cXMLHttp = this.cacheXMLHttp[i];
/* 如果XMLHttpRequesst的 readyState为0或4，确定当前对象闲置 */
if(cXMLHttp.readyState === 0 || cXMLHttp.readyState === 4){
return cXMLHttp;
}
}
/* 没有空闲创建对象 */
this.cacheXMLHttp[this.cacheXMLHttp.length] = this.createXmlHttp();
return this.cacheXMLHttp[this.cacheXMLHttp.length - 1];
},
/* 创建xmlhttp */
createXmlHttp: function(){
var methods = [
function(){ return new XMLHttpRequest();},
function(){ return new ActiveXObject('Msxml2.XMLHTTP');},
function(){ return new ActiveXObject('Microsoft.XMLHTTP');}
];
for(var i=0;i<methods.length;i++){
try{
methods[i]();
}catch(e){continue}
return methods[i]();
}
this.error('Could not create xmlhttp.');
},
/* 处理URL（增加随机参数，防止IE缓存服务器响应） */
makeURL: function(url){
var _s;
(url.indexOf('?') > 0)? _s = '&': _s = '?';
url += _s + 'rand-num-url=' + Math.random();
return url;
},
/* 设置请求头 */
setRequestHeader:{
html: "text/html",
xml: "application/xml, text/xml",
json: "application/json, text/javascript",
javascript: "text/javascript, application/javascript",
text: "text/plain",
},
/* 获取是否更新文件(针对html/xml/js) */
isNotLastModify: function (obj, url){
var lastModified = obj.getResponseHeader("Last-Modified");
var etag = obj.getResponseHeader("Etag");
this.lastModified[url] = [lastModified,etag];
return this.lastModified[url];
},
/* 工具类 */
parseJSON: function (data){
if(!data || typeof data != 'string'){
return null;
}
return eval('(' + data + ')');
},
/* 执行代码（JavaScript） */
conEval: function(data){
if(data){
var head = document.getElementsByTagName('head')[0].lastChild || document.documentElement.firstChild;
var script = document.createElement('script');
script.type = 'text/javascript';
script.appendChild(document.createTextNode(data));
this.insertAfter(script, head);
}
return data;
},
/* insertAfter(newElement, element) */
insertAfter: function(newEle, ele){
var _p = ele.parentNode;
(_p.lastChild == ele)? _p.appendChild(newEle) : _p.insertBefore(newEle, ele.nextSibling);
},
/* 判断类型输出处理结果 */
echoType: function(obj, type){
/* 获取相应content-type */
var _ct = obj.getResponseHeader("Content-Type") || '';
var xml = (type === 'xml' || _ct.indexOf('xml') >= 0);
var json = (type === 'json' || _ct.indexOf('json') >= 0);
var script = (type === 'javascript' || _ct.indexOf('javascript') >= 0);
var data = xml ? obj.responseXML : obj.responseText;
/* xml 结构错误 */
if(xml){
var er = data.documentElement.nodeName;
if( er == 'parsererror') this.error('XML parsererror.');
};
/* javascript xml */
if(typeof data === 'string'){
/* 处理json */
if(json) data = this.parseJSON(data);
/* 处理script */
if(script) data = this.conEval(data);
}
return data;
},
/* Error */
error: function(msg){
throw msg;
},
/* 定时器 */
setTimeOut: function(timer, fn){
setTimeout(fn, timer * 1000);
},
/* 处理服务器响应 */
request: function(G, callback){
/* 处理数据 */
//var method, url, data, type, timer, async;
method = G.method.toUpperCase();
url = G.url;
data = (method == 'POST')? this.hybridPar(G.data) : G.data;
type = G.type.toLowerCase();
timer = G.timer;
async = G.async;
/* 默认异步处理数据 */
if(async == null) async = true;
/* 创建xmlhttp对象 */
var xmlhttp = this.getFreeXMLHttp();
var firstUrl = url; /* 储存原始url */
if(method == 'GET') url = this.makeURL(url);
var that = this;/* 储存this */
/* 设置初始状态 */
var start = true;
/* _fn 结果综合处理函数 */
var _fn = function(){
if(xmlhttp.readyState !== 4) return;
if(xmlhttp.readyState === 4){
start = false;
if(xmlhttp.status === 200 || (xmlhttp.status === 304 && that.lastModified[firstUrl])){
that.isNotLastModify(xmlhttp, firstUrl);
if(typeof callback.success != 'undefined'){
if(xmlhttp.status === 200) callback.success(that.echoType(xmlhttp, type));
if(timer != null){
var _t = function(){
G.url = firstUrl;
that.request(G, callback);
};
that.setTimeOut(timer, _t)
}
}
}else{
if(typeof callback.failure != 'undefined'){
callback.failure(xmlhttp.status);
/* 重新发送错误请求 */
if(that.isDisp){
var _t = function(){
G.url = firstUrl;
G.timer = null;
that.request(G, callback);
}
that.setTimeOut(timer, _t);
}
}
}
}
}
/* async == true */
if(async == true) xmlhttp.onreadystatechange = _fn;
/* 打开与服务器连接 */
xmlhttp.open(method, url, async);
xmlhttp.setRequestHeader("Content-type",this.setRequestHeader[type.toLowerCase()]);
/* 设置请求头，当请求内容在指定的日期之后又经过修改才返回，否则返回 304(针对url被清缓存处理)*/
if( this.lastModified[firstUrl] && (type == 'xml' || type == 'html' || type == 'text' || type == 'javascript')){
xmlhttp.setRequestHeader("If-Modified-Since", this.lastModified[firstUrl][0]);
xmlhttp.setRequestHeader("If-None-Match", this.lastModified[firstUrl][1]);
}
xmlhttp.setRequestHeader("X-Requested-With", "XMLHttpRequest");
/* GET */
if(method === 'GET') data = null;
/* post 方式设置请求头 */
if(method == 'POST'){
/* post application/x-www-form-urlencoded*/
xmlhttp.setRequestHeader("Content-type","application/x-www-form-urlencoded");
}
this.isNotLastModify(xmlhttp, firstUrl);
xmlhttp.send(data);
/* async==false */
if(async == false) _fn();
},
/* 文件格式判断 */
fileLay: function (layout, ty){
var static = ['.html','.dhtml','.txt','.xml','.txt','.js'];
var trends = ['.php','.asp','.aspx','.jsp'];
var _, result = false;
if(ty == null) _ = static.concat(trends);
if(ty == 0) _ = static;
if(ty == 1) _ = trends;
/* 获取文件格式后缀 */
if(layout.indexOf('?') >= 0) layout = layout.substr(0, layout.indexOf('?'));
if(layout.lastIndexOf('/') >= 0) layout = layout.substr(layout.lastIndexOf('/') + 1, layout.length);
layout = layout.toLowerCase();
for(var i = 0, len = _.length; i < len; i++){
if(layout.indexOf(_[i]) >= 0) result = true;
}
return result;
},
/* (post方式)增加参数设置{'s':'1','t':'0'}/'s=1&t=0' */
hybridPar: function(data){
/* {'s':6,'t':'ui'}->s=6&t=ui */
if(typeof data == 'object'){
var _s = '';
for(var key in data){
_s = _s + key + '=' + escape(data[key]) + '&'
}
if(_s !== undefined){
if(_s.indexOf('&') >= 0) _s = _s.substr(0, _s.length - 1);
}else{
_s = null
};
return _s;
}
/* t=1&d=4&g=6 */
if(typeof data == 'string'){
return data;
}
},
/* Ajax.get */
get: function(calle, callback){
calle.method = 'get';
this.request(calle, callback);
},
/* Ajax.get */
post: function(calle, callback){
/* 静态文件不允许响应POST请求 */
calle.method = 'post';
if(this.fileLay(calle.url, 0) == true) calle.method = 'get';
this.request(calle, callback);
}
};