只接受优先选择的 UTF-8 iso-8859-1

请求：“ http://example.com ”

GET / HTTP/1.1
Host: example.com
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:53.0) Gecko/20100101 Firefox/53.0
Accept: text/html,application/xml;q=0.9,*/*;q=0.8
Accept-Charset: UTF-8, iso-8859-1;q=0.8
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Connection: keep-alive

客户端将接受 UTF-8 和 iso-8859-1 字符集，但更喜欢 UTF-8（质量因子为 1.0）。