What is the best way to profile javascript execution?

javascript performance browser profiling
Norbert Hartl picture Norbert Hartl · May 13, 2009 · Viewed 61.6k times · Source

Is there a good profiler for javascript? I know that firebug has some support for profiling code. But I want to determine stats on a longer scale. Imagine you are building a lot of javascript code and you want to determine what are actually the bottlenecks in the code. At first I want to see profile stats of every javascript function and execution time. Next would be including DOM functions. This combined with actions that slows things down like operation on the rendering tree would be perfect. I think this would give a good impression if the performance is killed in my code, in DOM preparation or in updates to the rendering tree/visual.

Is there something close to what I want? Or what would be the best tool to achieve the most of what I've described? Would it be a self compiled browser plus javascript engine enhanced by profile functionality?

Answer

geowa4 picture geowa4 · May 13, 2009

Firebug

Firebug provides a highly detailed profiling report. It will tell you how long each method invocation takes in a giant (detailed) table.

console.profile([title])
//also see
console.trace()

You need to call console.profileEnd () to end your profile block. See the console API here: http://getfirebug.com/wiki/index.php/Console_API

Blackbird

Blackbird (official site) also has a simpler profiler (can be downloaded from here)

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