Standard JSON encoding libraries, popular in web browser environments, do not support circular references (see Resources).

Web 浏览器环境经常使用的标准 JSON 编码库并不支持循环引用。 （见 参考资料）。

youdao

This may be conceptually sensible, but this button has a circular arrow symbol reminiscent of the "Back" button on a Web browser.

ENGADGET: Switched On: Jane, Stop This Crazy Thing