Yesterday I was profiling a page that used jQuery. The page took a long time to initialize. Firebug Profile (a great tool) told me that the time was in jQuery, but that wasn’t much help – the page initialization code had a lot of calls to jQuery, to bind functions to various page elements, and most of them were harmless.

Hence, jQuery.profile. Stick this in your page, call $.profile.start() to start profiling calls to $(selector), and then \$.profile.done() to stop profiling and print out something like this:

Selector                 Count  Total  Avg+/-stddev
script, script, scri...    100    101ms  1.01ms+/-1.01
script                   200     58ms  0.29ms+/-0.53
html body #output        100     55ms  0.55ms+/-0.74
script, #output          100     54ms  0.54ms+/-0.73
#output                  100      6ms  0.06ms+/-0.24


Or just include a ?jquery.profile.start query parameter in your page URL to begin profiling automatically as soon as the plugin is loaded.

The repository is on GitHub, so you can can comment here or fork it from there if you’ve got something to say.