无聊之后，看来我机器上的Chrome和FF已损坏，也许是因为注入了卡巴斯基脚本.重新安装W10已解决了该问题.抱歉.

After much boredom, it appears that Chrome and FF on my machine have been corrupted, perhaps by Kaspersky script injection. Re-installing W10 has solved the problem. Apologies.