Referrer Object
urlstring -HTTP Referrer URL.HTTP引用URL。policystring -Can be可以是default,unsafe-url,no-referrer-when-downgrade,no-referrer,origin,strict-origin-when-cross-origin,same-originorstrict-origin.default、unsafe-url、no-referrer-when-downgrade、no-referrer、origin、strict-origin-when-cross-origin、same-origin或strict-origin。See the Referrer-Policy spec for more details on the meaning of these values.有关这些值的含义的更多详细信息,请参阅Referrer策略规范。