I used to think so. Then I read the spec: http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2 http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec

I used to think so. Then I read the spec: http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2 http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2 The field value MAY be preceded by any amount of LWS, though a single SP is preferred. For the definition of SP and LWS, see: http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2 http://www.w3.org/Protocols/rfc2616/rfc2616-sec2.html#sec2.2 For the definition of MAY, see: https://www.ietf.org/rfc/rfc2119.txt https://www.ietf.org/rfc/rfc2119.txt