Status: Unknown

The page analyzer analyzes your web page performance by emulating how a web browser would load your page and all resources referenced in it. The page and its referenced resources are loaded and important performance metrics are measured and displayed in a load-bar diagram along with other per-resource attributes such as URL, size, compression ratio and HTTP status code. Each bar has parts of different color corresponding to a performance metric:

• Time in queue: the time a resource is idle in the browser queue waiting to be downloaded.
• DNS lookup time: the time it takes to resolve the host name into an IP-address.
• Connect time: the time it takes to establish a connection with the server.
• Redirect time: the time lost due to a redirect, a response with a HTTP status code of 301, 302, 303 or 307.
• Time to first byte: the time it took to receive the first byte from the server.
• Download time: the time spent downloading the resource.

Note: Javascript code is not executed. Resources loaded using Javascript might not be be discovered, loaded and measured.

The page analyzer is capable of emulating a number of well-known web browsers:

• Chrome 1, 2, 3 and 4
• Firefox 2, 3 and 3.5
• Internet Explorer 6, 7 and 8
• Opera 9.64
• Safari 3 and 4

The following well-known indexing bots can also be used:

• GoogleBot 2.1
• MSNBot 1.1
• Yahoo! Slurp

The following parameters are emulated:

• Max allowed connections
• Max allowed persistent-connections per host
• If scripts are allowed to be downloaded in parallel (*)
• If external stylesheets block parallel downloads of other resources (*)
• If an external stylesheet followed by an inline script blocks parallel downloads (*)
• If external scripts block parallel downloads of other resources (*)
• Conditional comments (**)
• CSS 2.1/3 cascading.
• User-Agent header string set to the user-agent emulated
• Accept-Charset header string
• Accept-Encoding header string to handle compressed resources (gzip, deflate and bzip2)
• Accept-Language header string to emulate user language preference

(*) - See http://stevesouders.com/ua/ for more information on web-browser behaviour.
(**) - See http://msdn.microsoft.com/en-us/library/ms537512(VS.85).aspx for more information.