You can do AJAX calls with AjxRpc.
Example of a GET request (take care to add the domain of the php page to the proxy allowed domains) :
Code:
params = "?param="+ information;
//Setting the URL
url = ZmZimletBase.PROXY + AjxStringUtil.urlComponentEncode(urlPhpPage + params);
//the AJAX call.
var response = AjxRpc.invoke(null, url , null, null, true);