// 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("Msxml2.XMLHTTP");
				  } catch (e)
          {
				    try
            {
		        	this.httprequest = new ActiveXObject("Microsoft.XMLHTTP");
						} catch (e) {}
					}
			}// End if

      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();
			}
		}// End if
	},
	processaerro:		function()
  {
		alert(this.httprequest.status + '-' + this.httprequest.statusText + ' :-> ' + this.url);
	}
}// End prototype