ifrmae跨域代码案例，原理是A页面访问B页面出现跨域，此时在A站点下建立代理C，B页面ifr a me中调用C去访问A，形成代理从而解决ifr a me跨域-ifrmae inter-code case, the principle is the A page B page appears cross-domain access, this time in the A site created under the agency C, B calls C the ifr a me page t