How the Cache-control of HTTP request headers and response headers are understood

HTTP request header and response header Cache-control how to understand
Web site is WordPress, the request of Cache-control is No-cache, in response to the head is I set in Nginx max-age=259200, then the browser in the end cache no ...

Request Headersview Source
accept:*/*
Accept-encoding:gzip, deflate, SDCH
accept-language:zh-cn,zh;q=0.8
Cache-control:no-cache
Connection:keep-alive
cookie:cnzzdata1254790698=1245005062-1429681029-%7c1429681029
Host:yuanzi.me
Pragma:no-cache
referer:http://yuanzi.me/
user-agent:mozilla/5.0 (Windows NT 6.1; WOW64) applewebkit/537.36 (khtml, like Gecko) chrome/39.0.2171.95 safari/537.36

Response Headersview Source
Accept-ranges:bytes
cache-control:max-age=259200
Connection:keep-alive
content-length:100922
Content-type:application/javascript
date:wed, APR 06:13:34 GMT
ETag: "55371597-18A3A"
Expires:sat, APR 06:13:34 GMT
last-modified:wed, APR 03:29:27 GMT
server:nginx/1.6.2

------to solve the idea----------------------
If there is cache-control=no-cache in the response header then the browser is not cached
But your response header is not, so there should be a cache.
However, even if there is a cache, it is not necessarily used by browsers. Because the browser also has other settings
And not the cache-related header will be accepted by the browser, the protocol is only a recommendation, not a must be executed

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