1. You can use Ajax to access the upper level proxy page, get the data, and then pass the data to the lower level proxy page.
2. You can use JSONP to access the upper proxy page across domains, then fetch data, and then pass it to the lower proxy page.
3. You can use iframe to view the content of the upper-level proxy page as the content of the iframe, and then access the iframe in the lower-level proxy page to obtain the data of the upper-level proxy page.
