//扩充系统自带的try语句
var Try = {
  these: function() {
    var returnValue;

    for (var i = 0, length = arguments.length; i < length; i++) {
      var lambda = arguments[i];
      try {
        returnValue = lambda();
        break;
      } catch (e) { }
    }

    return returnValue;
  }
}

//为Object对象增加，扩充方法，此方法用来给指定函数
Object.extend = function(destination, source) {
  for (var property in source)
    destination[property] = source[property];
  return destination;
}

//通过标签ID获取对象
function GE(a){return document.getElementById(a);} 


//自定义AJAX对象
var Ajax = function(ShowID,ShowMeth) {
	
//私有变量
	var _xmlHttp=Object;
	var Chrset=new GB2312UTF8();

//共有变量
	this.url='';		//请求的页面
	this.method='POST';
	this.isAsync=true;
	this.contentType='application/x-www-form-urlencoded';
	this.headerType='Content-Type';
	this.data='';		//传送的数据
	
//私有函数	
	//创建异步传输对象
	getTransport= function() {
		return Try.these(
			function() {return new XMLHttpRequest()},
			function() {return new ActiveXObject('Msxml2.XMLHTTP')},
			function() {return new ActiveXObject('Microsoft.XMLHTTP')}
		) || false;
	};
	
	//向消息对象发送HTML消息，如果消息对象不存在则用消息提示框提示信息
	_showMsg=function(_data,selSW)
	{
		if(arguments.length==1 || selSW>2 || selSW<0 || ShowID==null)
			selSW=0;
		
		switch(selSW)
		{
			case 0:
				alert(_data);
				break;
			case 1:
				GE(ShowID).innerText=_data;
				break;
			case 2:
				GE(ShowID).innerHTML=_data;
				break;
			case 3:
				eval(_data);
				break;
		}
	};
	
	 this._readystatechange=function(){ 
		if(_xmlHttp.readyState==4)
		{
			if(_xmlHttp.status==200)
			{
				_showMsg(Chrset.Utf8ToGb2312(_xmlHttp.responseText),ShowMeth);
				_xmlHttp=null;
				return true;
			}
			else
			{
				_showMsg("出错了!Err@server:" + _xmlHttp.status,0);
				_xmlHttp=null;
				return true;
			}
		}
		else
		{
		}
	};
	
//共有函数
	this.open=function(){
		_xmlHttp.open(this.method, this.url, this.isAsync);
	};
	
	this.Request=function(){
		_xmlHttp=getTransport();
		if(Boolean(_xmlHttp)==false)
		{
			_showMsg('你的浏览器不支持XMLHTTP，无法使用AJAX技术！',1);
			return false;
		}
		//传输信息至服务器
		_xmlHttp.onreadystatechange=this._readystatechange; 
		this.open();
		_xmlHttp.setRequestHeader(this.headerType,this.contentType); 
		_xmlHttp.send(this.data);

	};
}


/*
 * GB2312转UTF8
 * 例：
 * var xx=new GB2312UTF8();
 * var Utf8=xx.Gb2312ToUtf8("你aaa好aaaaa");
 * var Gb2312=xx.Utf8ToGb2312(Utf8);
 * alert(Gb2312);
 */

function GB2312UTF8(){
  this.Dig2Dec=function(s){
      var retV = 0;
      if(s.length == 4){
          for(var i = 0; i < 4; i ++){
              retV += eval(s.charAt(i)) * Math.pow(2, 3 - i);
          }
          return retV;
      }
      return -1;
  } 
  this.Hex2Utf8=function(s){
     var retS = "";
     var tempS = "";
     var ss = "";
     if(s.length == 16){
         tempS = "1110" + s.substring(0, 4);
         tempS += "10" +  s.substring(4, 10); 
         tempS += "10" + s.substring(10,16); 
         var sss = "0123456789ABCDEF";
         for(var i = 0; i < 3; i ++){
            retS += "%";
            ss = tempS.substring(i * 8, (eval(i)+1)*8);
            retS += sss.charAt(this.Dig2Dec(ss.substring(0,4)));
            retS += sss.charAt(this.Dig2Dec(ss.substring(4,8)));
         }
         return retS;
     }
     return "";
  } 
  this.Dec2Dig=function(n1){
      var s = "";
      var n2 = 0;
      for(var i = 0; i < 4; i++){
         n2 = Math.pow(2,3 - i);
         if(n1 >= n2){
            s += '1';
            n1 = n1 - n2;
          }
         else
          s += '0';
      }
      return s;      
  }

  this.Str2Hex=function(s){
      var c = "";
      var n;
      var ss = "0123456789ABCDEF";
      var digS = "";
      for(var i = 0; i < s.length; i ++){
         c = s.charAt(i);
         n = ss.indexOf(c);
         digS += this.Dec2Dig(eval(n));
      }
      return digS;
  }
  this.Gb2312ToUtf8=function(s1){
    var s = escape(s1);
    var sa = s.split("%");
    var retV ="";
    if(sa[0] != ""){
      retV = sa[0];
    }
    for(var i = 1; i < sa.length; i ++){
      if(sa[i].substring(0,1) == "u"){
        retV += this.Hex2Utf8(this.Str2Hex(sa[i].substring(1,5)));
		if(sa[i].length){
		  retV += sa[i].substring(5);
		}
      }
      else{
	    retV += unescape("%" + sa[i]);
		if(sa[i].length){
		  retV += sa[i].substring(5);
		}
	  }
    }
    return retV;
  }
  this.Utf8ToGb2312=function(str1){
        var substr = "";
        var a = "";
        var b = "";
        var c = "";
        var i = -1;
        i = str1.indexOf("%");
        if(i==-1){
          return str1;
        }
        while(i!= -1){
		  if(i<3){
                substr = substr + str1.substr(0,i-1);
                str1 = str1.substr(i+1,str1.length-i);
                a = str1.substr(0,2);
                str1 = str1.substr(2,str1.length - 2);
                if(parseInt("0x" + a) & 0x80 == 0){
                  substr = substr + String.fromCharCode(parseInt("0x" + a));
                }
                else if(parseInt("0x" + a) & 0xE0 == 0xC0){ //two byte
                        b = str1.substr(1,2);
                        str1 = str1.substr(3,str1.length - 3);
                        var widechar = (parseInt("0x" + a) & 0x1F) << 6;
                        widechar = widechar | (parseInt("0x" + b) & 0x3F);
                        substr = substr + String.fromCharCode(widechar);
                }
                else{
                        b = str1.substr(1,2);
                        str1 = str1.substr(3,str1.length - 3);
                        c = str1.substr(1,2);
                        str1 = str1.substr(3,str1.length - 3);
                        var widechar = (parseInt("0x" + a) & 0x0F) << 12;
                        widechar = widechar | ((parseInt("0x" + b) & 0x3F) << 6);
                        widechar = widechar | (parseInt("0x" + c) & 0x3F);
                        substr = substr + String.fromCharCode(widechar);
                }
			  }
			  else {
			   substr = substr + str1.substring(0,i);
			   str1= str1.substring(i);
			  }
              i = str1.indexOf("%");
        }

        return substr+str1;
  }
}