function BASE(){
		if(window.XMLHttpRequest) {
			try {
				req = new XMLHttpRequest();
	        } catch(e) {
				req = false;
	        }
		} else if(window.ActiveXObject) {
	       	try {
	        	req = new ActiveXObject("Msxml2.XMLHTTP");
	      	} catch(e) {
	        	try {
	          		req = new ActiveXObject("Microsoft.XMLHTTP");
	        	} catch(e) {
	          		req = false;
	        	}
			}
	    }

		if(req){
			this.HTTP = req;
			this.error = ""
		}else{
			this.HTTP = null;
			this.error = "El Navegador no soporta HTTP_REQUEST."
		}
		
		this.result = new Object();
		this.commandFile = "";
		this.params = "";
	}
	
	BASE.prototype.send = function(parameter){
		if(this.HTTP != null){
			this.parameter = parameter == undefined ? this.parameter : parameter;
			this.parameter = this.parameter + "&commandfile="+this.commandFile;
			this.HTTP.open("POST", "/clinicamagallanes/componente/database/classNS.php" , false);
			this.HTTP.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded;charset=ISO-8859-1;');
			//try { this.HTTP.setRequestHeader("User-Agent","ROCKEROX"); } catch (ex) {}
			this.HTTP.send(this.parameter);
			if (this.HTTP.status == 200) {
				this.result = this.getResult(this.HTTP);
			}else{
				this.result.error = "Error: "+this.HTTP.status +"\n"+ this.HTTP.statusText;
			}
			return this.result;
		}else{
			alert(this.error);
			return null;
		}
	}

	BASE.prototype.sendAsync = function(parameter,functionName){
		if(this.HTTP != null){
			this.parameter = parameter == undefined ? this.parameter : parameter;
			this.parameter = this.parameter + "&commandfile="+this.commandFile;
			this.HTTP.open("POST", "/clinicamagallanes/componente/database/classNS.php" , true);
			this.HTTP.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded;charset=ISO-8859-1;');
			//try { this.HTTP.setRequestHeader("User-Agent","ROCKEROX"); } catch (ex) {}
			this.HTTP.onreadystatechange = functionName;
			this.HTTP.send(parameter + "&commandfile="+this.commandFile);
		}
	}
	
	BASE.prototype.getResult = function(Connection){
		var result = new Object();
		result.numfields = 0;
		result.numrows = 0;
		result.error = "";
		result.data = null;
		try{
			result.data =  Connection.responseXML.documentElement.getElementsByTagName("table")[0];
			result.numfields = unescape(result.data.getAttribute("numfields"));
			result.numrows = unescape(result.data.getAttribute("numrows"));
			result.error = unescape(result.data.getAttribute("error"));
		}catch(ex){
			result.error = Connection.responseText;
		}
		return result;
	}
	
		
	BASE.prototype.getField = function(_result,_campo,_indice){
		try{
			if(isNaN(_campo)){
				var _value = unescape(_result.data.getElementsByTagName("record")[_indice].getElementsByTagName(_campo)[0].firstChild.nodeValue);
			}else{
				var _value = unescape(RS.data.getElementsByTagName("record")[0].childNodes[_campo].firstChild.nodeValue);
			}
			_value = _value.replace('#NULL#','') ;
		}catch(exception){
			alert("Error: No se puede leer el valor de "+_campo);
			var _value = null;
		}
		return _value;
	}
	
	
	BASE.prototype.getResponse = function(Connection){
		var Data = "";
		try{
			Data =  Connection.responseText;
		}catch(exception){
			result.error = "ERROR: No es posible abrir el recordset. \nDescripción:\n"+exception.message;
		}
		return Data;
	}