function CrearAjax() {
	var ro;
	var browser = navigator.appName;
	if(browser == "Microsoft Internet Explorer"){
		ro = new ActiveXObject("Microsoft.XMLHTTP");
	}else{
		ro = new XMLHttpRequest();
	}
	return ro;
}

function sendAjax(page, params, functionCallBackName){ 
	var ajaxObj = CrearAjax();
	var callBackFunction = '';
	var dir = page+'?'+params;	
	ajaxObj.onreadystatechange= function(){
					if(ajaxObj.readyState == 4){							
						var res = ajaxObj.responseText;						
						callBackFunction  = functionCallBackName;
						callBackFunction += '(\''+res+'\');';
						eval(callBackFunction);												
					}
				};
	ajaxObj.open('post', dir, true);
	ajaxObj.send(null); 
}