The actions listed on this tab provide a breakdown of the operations required to process the selected requested:

Display URL

This action indicates that the browser started processing a URL request and will complete the request in one of three ways:

• If a suitable entry exists in the browser cache, it will be used directly and the Result column will show (Cache)
  
• If a cache entry exists but has expired or has no expiration date, The browser will send a GET request with an If-Modified-Since header
  
• If there is no entry in the browser cache, then an unconditional HTTP GET request will be sent

Resync URL

The browser started a refresh operation because the user pressed F5 or clicked on the Refresh toolbar icon. This will be processed in one of two ways:

• If there is an entry in the browser cache it will be validated using an If-Modified-Since header regardless of any expiration date that has been previously set.
  
• If no entry exists in the browser cache, an unconditional HTTP GET request will be sent.

Get Latest

The browser is performing a forced update operation, typically due to the user pressing Ctrl + F5. This is always processed as an unconditional GET or POST request.

Submit Form

This is usually the result of an HTML form being submitted and causes an HTTP POST to be sent to the web server.

Started At

This action shows the date and time at which the browser started to process the HTTP transaction. The request may not be immediately sent out on the network due to the following factors:

• The request will be blocked if there are too many outstanding requests to the same server or proxy. It is often this delay that is the most significant factor for the time taken to retrieve an image.
  
• The host name may need to be resolved into an IP address see DNS Lookup below.
  
• A new connection may be required if an existing connection cannot be reused.

DNS Lookup

The browser is resolving a host name, such as www.microsoft.com, into an IP address, e.g. 207.46.244.188, prior to attempting a connection to the web server .

Connecting

Indicates that no existing connection to the server was available for use by this request and the browser is creating a new TCP connection to the specified IP address.

Connected

A new connection has been made to the server using the specified local IP address and port number (<ip>:<port>).

Connection Reuse

An existing connection to the server was used by this request instead of a new connection.

HTTP Request

This shows that an HTTP request that was sent over the network to the server.

HTTP Response

This shows that an HTTP response was received from the web server.

Read Cache

This action can occur in three situations:

1. The browser sent an If-Modified-Since header and received a 304 Not Modified response. The content would then be read from the cache because the 304 response indicates that it is still valid. The Content-Length header in the response will always be zero or absent because the HTTP 1.1 spec defines the 304 status code as never returning content.
   
2. The browser decided not to send a HTTP GET request because there is an entry in the browser cache that either has a valid expiration date or has been recently checked. The Result column will show (Cache) in these cases.
   
3. The browser is in 'Work Offline' mode

Redirect

The web server returned a 3xx response (usually 301 or 302) that redirected the browser to a different URL.