Do you remember JsonP ?
Here I give you the XmlP …
AjaxProxy cannot be used to retrieve data from other domains. If your application is running on http://domainA.com it cannot load data from http://domainB.com because browsers have a built-in security policy that prohibits domains talking to each other via AJAX.
If you need to read data from another domain and can't set up a proxy server (some software that runs on your own domain's web server and transparently forwards requests to http://domainB.com, making it look like they actually came from http://domainA.com), you can use Ext.data.proxy.XmlP and a technique known as Xml-P (Xml with Padding), which can help you get around the problem so long as the server on http://domainB.com is set up to support Xml-P responses. The XmlP is based on Default JsonP created by Ed Spencer. Just a little modification add for working with XML. See http://market.sencha.com/addon/xmlp for more details.