ajax请求node.js接口时出现 No 'Access-Control-Allow-Origin' header is present on the requested resource错误

ajax请求node.js接口出现了如下的错误：

XMLHttpRequest cannot load http://xxx.xxx.xx.xx:8888/getTem?cityId=110105&date=2015-03-04. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'null' is therefore not allowed access.

百度了一下，原来是缺少Access-Control-Allow-Origin属性，那么在node.js输出时把Access-Control-Allow-Origin属性加上就好了，如下

response.writeHead(200, {'Content-Type': 'text/json;charset=utf-8','Access-Control-Allow-Origin':'*'});

谷歌查了一下，原来Access-Control-Allow-Origin来限制请求域名的。 点我查看该属性的解释