SharePoint跨域访问

<script type="text/javascript" src="/_layouts/15/sp.runtime.js"></script><script type="text/javascript" src="/_layouts/15/sp.js"></script><script type="text/javascript" src="/_layouts/15/SP.RequestExecutor.js"></script>var context = new SP.ClientContext(addinweburl);var factory =  new SP.ProxyWebRequestExecutorFactory(addinweburl);context.set_webRequestExecutorFactory(factory);var web = context.get_web();var list = web.get_lists().getByTitle("Announcements");