简单的Ajax类和DataSet数据集

[Ajax类]

function Ajax(){	
	this.xmlhttp = null;        //XML对象
	this.method = "post";       //执行的方法(post/get)
	this.url = "";              //异步调用的页面地址
    this.responseText = "";         //异步返回的响应字符串   
    this.responseXML = "";          //异步返回的响应XML 	
	this.failed = false;        //创建对象错误标志
	this.synch = false;         //同步false/异步true
	
	/******************** 事件 ************************/
    this.onLoading = function() {};     //正在发送请求   
    this.onLoaded = function() {};      //已经接收到全部响应内容   
    this.onInteractive = function() {}; //正在解析响应内容   
    this.onCompletion = function() {};  //响应内容解析完成   
    this.onError = function() {};       //异步错误处理事件   
    this.onFail = function() {};        //创建对象失败处理世界
    
    /******************** 重置事件 **********************/ 
    this.resetFunctions = function() {   
        this.onLoading = function() {};   
        this.onLoaded = function() {};   
        this.onInteractive = function() {};   
        this.onCompletion = function() {};   
        this.onError = function() {};   
        this.onFail = function() {}; 
    };
    
    /******************* 函数 ********************/ 
    //初始化
    this.init = function(){   
        if(window.XMLHttpRequest){   
            this.xmlhttp = new XMLHttpRequest();   
        }else if (window.ActiveXObject){   
            try{this.xmlhttp = new ActiveXObject("Msxml4.XMLHTTP");}   
            catch(e){   
                try{this.xmlhttp = new ActiveXObject("Msxml3.XMLHTTP");}   
                catch(e){   
                    try{this.xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");}   
                    catch(e){   
                        try{this.xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");}   
                        catch(oc){this.failed=true;}   
                    }   
                }   
            }   
        }   
    };


     
    //发送请求
    //@param data 发送的数据  
    //@example send("id=1");  
    this.send=function(data){
        var self=this;   
        if(this.method=="post") {   
            this.xmlhttp.open(self.method,self.url,self.synch);   
        }else{   
            this.xmlhttp.open(self.method,self.url+"?"+encodeURI(data),self.synch);   
        }   
        //添加消息响应头   
        this.xmlhttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded;charset=utf-8");   
           
        //异步回调函数   
        this.xmlhttp.onreadystatechange = function(){
            //对象未创建   
            if (self.failed) {   
                self.onFail();   
                return;   
            }   
               
            //消息响应标志   
            switch (self.xmlhttp.readyState) {  
                //（未初始化）还没有调用send()方法
                case 0:{
                
                    break;
                } 
                //（载入）已调用send()方法，正在发送请求
                case 1:{   
                    self.onLoading();   
                    break;   
                }
                //（载入完成）send()方法执行完成，已经接收到全部响应内容 
                case 2:{   
                    self.onLoaded();   
                    break;   
                }
                //交互）正在解析响应内容
                case 3:{   
                    self.onInteractive();   
                    break;   
                }
                //完成）响应内容解析完成，可以在客户端调用了
                case 4:{   
                
                    /*
                    1**：请求收到，继续处理
                    2**：操作成功收到，分析、接受
                    3**：完成此请求必须进一步处理
                    4**：请求包含一个错误语法或不能完成
                    5**：服务器执行一个完全有效请求失败
                    */
                    switch(self.xmlhttp.status){
                        case 200 : {
                            self.responseText = self.xmlhttp.responseText;   
                            self.responseXML = self.xmlhttp.responseXML; 
                            break;
                        }
                        case 500 : {
                            self.onError();
                            break;
                        }
                    }
                    self.onCompletion();
                    break;   
                }   
            }   
        };   
        
        if(this.method=="post"){   
            this.xmlhttp.send(data); //发送请求   
        }else{   
            this.xmlhttp.send();     //发送请求   
        }   
    };
    
    this.abort=function(){   
        this.xmlhttp.abort();   
    }   
       
    this.close=function(){   
        this.xmlhttp=null;   
    }   
    this.init();   
}

[DataSet数据集]

// 将responseXML封装成数据集的类 
function RecordSet(xml,recordName)
{
	var records = xml.getElementsByTagName(recordName);
	this.recordCount = records.length;
	var current_index = 0;
	var items = [];
	
	if(this.recordCount > 0){
		items = createFields(records[current_index]);
		this.items = items;
	}
	//记录集下移
	this.next = function(){
		if(current_index < this.recordCount -1){
			current_index += 1;
			items = createFields(records[current_index]);
			this.items = items;
		}
	}
	//记录集上移 
	this.previous = function(){
		if(current_index > 0){
			current_index -= 1;
			items = createFields(records[current_index]);
			this.items = items;
		}
	}
	//记录集上移至第一个记
	this.first = function(){
		current_index = 0;
		if(this.recordCount > 0){
			items = createFields(records[current_index]);
			this.items = items;
		}
	}
	//记录集上移至最后一个记录
	this.last = function() {
		current_index = this.recordCount - 1;
		if(this.recordCount > 0){
			items = createFields(records[current_index]);
			this.items = items;
		}
	}
	this.GotoRow = function(rowindex) {
	    if(rowindex == 0){
	        this.first();
	    }else{
	        if(this.recordCount > 0 && rowindex > 0 && rowindex < this.recordCount){
	            current_index = rowindex;
	            items = createFields(records[current_index]);
			    this.items = items;
		    }
	    }	
	}
}
// 构造记录的Field数组 
function createFields(record){
	var items = new Array();
	var childNodes = record.childNodes;
	for(var i=0;i<childNodes.length;i++){
		var item = new Object();
		item.name = childNodes.item(i).tagName;
		item.value = childNodes.item(i).text;
		items[items.length] = item;
		items[item.name] = item;
		
	}
	return items;
}