// Objeto AJAX para comunicação Assincrona com um servidor de aplicações WEB

function AJAX(url,metodo,params,processa,modo)
{
this.url = url;
this.metodo = (metodo) ? metodo : 'GET';
this.params  = (metodo='GET') ? null : params;
this.processaresultado = processa;
this.Header = new Array();
this.modo = (modo) ? modo : 'T';
if (this.modo!='T'&&this.modo!='X')
   {
     this.modo = 'T';
   }
this.conectar();
}

AJAX.prototype = {

addHeader: function(h,v)
                   {
                     this.Header[h] = v;
                   },

delHeader: function(h)
                   {
                     delete(this.Header[h]);
                   },

setHeader:	function()
                    {
                      if(this.httprequest==null) { return;}
					  for(h in this.Header)
                         {
                           this.httprequest.setRequestHeader(h,this.Header[h]);
                         }
                    },

conectar: function()
                  {
                    if(this.url==undefined||this.url=='')
                      {
                        return;
                      }
                    this.httprequest = null;
                    if (window.XMLHttpRequest)
                       { // Mozilla, Safari,...
                         this.httprequest = new XMLHttpRequest();
                       }
                    else if (window.ActiveXObject)
                            { // IE
                              try {
                                    this.httprequest = new ActiveXObject("Msxml.XMLHTTP");
                                  }
                              catch (e)
                                    {
                                      try {
                                            this.httprequest = new ActiveXObject("Microsoft.XMLHTTP");
                                          }
                                      catch (e) {}
                                    }
                            }
                    if(this.httprequest!=null&&this.httprequest!=undefined)
                      {
                        var obj = this;
                        this.httprequest.onreadystatechange = function()
                                                                      {
                                                                        obj.processaretorno.call(obj);
                                                                      }
						if(this.metodo==undefined||this.metodo=='')
                          {
                            this.metodo = 'GET';
                          }
			        	this.httprequest.open(this.metodo,this.url, true);
						this.setHeader();
						this.httprequest.send(this.params);
                      }
                  },

processaretorno: function()
                         {
                           if(this.httprequest.readyState==4)
                             {
                               if(this.httprequest.status==200)
                                 {
                                   var resp=(this.modo=='T') ? this.httprequest.responseText : this.httprequest.responseXML;
                                   if(this.processaresultado!=null)
                                     {
                                       this.processaresultado(resp);
									 }
                                   else
                                      {
                                        document.write(resp);
                                      }
								 }
                               else
                                  {
									this.processaerro();
								  }
                             }
                         },

processaerro: function()
                      {
                        alert(this.httprequest.status + '-' + this.httprequest.statusText + ' :-> ' + this.url);
                      }
}