function Ajax(){var thisInstance = this; var httpRequest= null; this.listeners = null; this.open= open;this.send= send;this.getReadyState = getReadyState; this.getResponseText = getResponseText;this.addEventListener= addEventListener;this.removeEventListener = removeEventListener; this.dispatchEvent = dispatchEvent; if (window.XMLHttpRequest){httpRequest = new XMLHttpRequest();}else if(window.ActiveXObject){ try {httpRequest = new ActiveXObject("Msxml2.XMLHTTP");}catch(e){try {httpRequest = new ActiveXObject("Microsoft.XMLHTTP");}catch(e){alert('Problema al Iniciar Ajax');}}}function addEventListener(type, listener, useCapture){this.listeners = listener;}function removeEventListener(type, listener, useCapture){}function dispatchEvent(evt){this.listeners.handleEvent(evt);}function getReadyState(){return httpRequest.readyState;}function getResponseText(){if(httpRequest.status == 200){return httpRequest.responseText;}else{alert('Ajax.getResponseText(): El estado no es 200');}}function open(method,url,async,user,password){if(httpRequest.overrideMimeType){httpRequest.overrideMimeType('text/plain');}httpRequest.open(method,url,async,user,password);httpRequest.onreadystatechange = onReadyStateChange;}function send(data){httpRequest.send(data);}function onReadyStateChange(e){thisInstance.dispatchEvent(thisInstance);}}