这是一个google广告的请求，分为5部分，依次如下：
白色：空白时间，0.001s，表示页面刷新后0.001s才开始这个请求。
绿色：请求发送时间，也是0.001秒
红色：等待时间，这个影响因素较多，网络、数据库查询等等。
青色：请求接收，这条请求结果只返回了304的请求状态，所以时间很短，上图几乎看不到。
蓝色：从浏览器缓冲中读取，因为返回304，表示该文件最后更新日期没有发生改变，所以从缓存中读取
该文件。
两 次请求有什么不同，第一次200请求成功请求，所以接受的数据大小为js的大小15.9K，第二次304，只返回
一个状态，表示该文件最后更新时间没有改 变，文件可以从浏览器缓存中取得。从这也可以看出在ie中点刷新
和在地址栏打回车并不一样，点刷新素有文件都会像服务器发送请求，只是如果文件被缓存，只 返回304状态，
在地址栏打回车时，缓存的内容不会像服务器发送请求，直接从缓存中获取，httpwatch中result中显示为(cach
e)。当然 点击每一条明细，也可以在下面的详细信息中查看是否被缓存，如何缓存，过期时间、健等信息。
还有其他信息，如cookies、queryString等信息，这里就不一一列举，大家多使用使用就熟悉了。
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httpwatch7 <wbr>timechart <wbr>解析The Blocked time includes any pre-processing time (such as cache
lookup) and the time spent waiting for a network connection to become available. Internet Explorer will only
create a maximum of two concurrent network connections per host name (i.e. www.microsoft.com) and wil
queue up requests until a network connection is available. Often the Blocked time is the most significant facto
r in the download time of images embedded in a web page.
Connect is the time required to create a TCP connection to the web server (or proxy). If a secure HTTPS conn
ection is being used this time includes the SSL handshake process. Keep-Alive connections are often used to av
oid the overhead of repeatedly connecting to the web server.
Send is the time required to send the HTTP request message to the server and will depend on the amount of d
ata that is sent to the server. For example, long Send times will result from uploading files using an HTTP POST
Wait is the idle time spent waiting for a response message from the server. This value includes delays introduce
d due to network latency and the time required to process the request on the web server.
等待，是花费在等待服务器响应消息的空闲时间，这个值包括网络延迟和服务器处理请求的时间。
Receive is the time taken to read the response message from the server. This value will be depend on the size o
f the content returned, network bandwidth and whether HTTP compression was used.
Cache Read is the time taken to read the content from the browser cache during (Cache) or 304 responses.
缓存读取，是花费在从浏览器缓存中读取内容或者304响应的时间。
TTFB (or Time To First Byte) is the duration from the initial network request being initiated by the browser to th
e first byte being received from the server. It includes TCP connection time, the time to send the request and
the time taken to get the first byte of the response message.