Chrome Console工具
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Protocol字段::

    1. HTTP/1.1: the "classic" HTTP protocol
    2. SPDY/3.1: Google's first version of the HTTP/2 spec, formed the basis of HTTP/2
    3. H2-14: H2 stands for "HTTP 2", the 14 will refer to "draft 14" since the HTTP/2 spec isn't final yet
    4. H2C-14: H2C stands for "HTTP 2 Cleartext", the HTTP/2 protocol over a non-encrypted channel