Missing 'DomContentLoaded' and 'load' time information in Firebug's Net Panel.

Question

Hello,

Firebug is awesome in reporting the relative time when an HTTP request was made with respect to the 'DomContentLoaded' and 'load' time. However, once the 'load' event occurs (seen by the red line on the timeline), the requests thereafter do not have any information about how later they occurred with respect to the two events.

To confuse things, these requests (usually at the bottom of the timeline) appear to have started right at the beginning of the page load. Could somebody shed some light on what should i infer when i see such entries in the timeline which do not have information about the 'DomContentLoaded' and 'load' event times and appear to have occurred after the page load event, still net panel shows that they started at the beginning?

Thanks!

Answer 1

the load and DOMContentLoaded events occur when all the files referenced from the initial html page are retrieved. In the case of DOMContentLoaded, the event happens when the initial DOM for the page is fully loaded. Files loaded from the initial html document will be displayed relative to that document on the timeline.

Additional network traffic can occur as soon as JavaScript begins execution, often through XmlHttpRequests to the originating or another server. These requests won't have the progress events (loaded, DOMContentLoaded) displayed when you hover over them. Because these requests can be fired off based on events happening within the web application, they may be shown out of sequence, their left edge lining up with the original requests for the web page. It's best not to think of the timeline is a linear sequence for these requests and responses, but more of a grid containing different representations of traffic as it occurs in real-time.

hope this helps!

Answer 2

Here is an actual answer to my original question: http://www.softwareishard.com/blog/firebug/firebug-net-panel-timings/