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Try… Catch Benchmark

Intermediate Matt Hackett Published June 15th, 2008 by Matt Hackett

The try...catch statement in JavaScript is a common tool, especially useful in a programming environment as volatile as the web. Since I always try to make my scripts execute as quickly as possible, I was curious about the performance hit when using try...catch extensively. Below is a benchmark testing three methods:

  1. A simple, bare-bones variable definition
  2. The same code, but with a try...catch block
  3. The same code, but with a try...catch block and an intentional error

Here's the source code:

As you can see, each test is executed 10,000 times to get a good sampling of how long each is taking. Please note that this script could lock up your browser for a few moments (or even crash it), but you can run this benchmark yourself below:

Results:
  • Solo: execute to view
  • With try...catch statement: execute to view
  • With try...catch statement and an error: execute to view

Using Windows XP, I executed this script ten times using each of the common browsers, taking the averages and compiling them in the table below:

Browser Solo With try...catch With try...catch and an error
Firefox 2 36 milliseconds 47 milliseconds 32.917 seconds
Firefox 3 3 milliseconds 4 milliseconds 156 milliseconds
Google Chrome 0 milliseconds 6 milliseconds 69 milliseconds
Internet Explorer 6 33 milliseconds 35 milliseconds 209 milliseconds
Internet Explorer 7 33 milliseconds 35 milliseconds 178 milliseconds
Opera 6 milliseconds 10 milliseconds 3.011 seconds
Safari 3 13 milliseconds 16 milliseconds 50 milliseconds

Based on this benchmark, it appears that try...catch adds negligible overhead on its own; it's the handling of errors that can add signifant execution time to your scripts. Internet Explorer and Safari seem to handle errors very quickly, while Opera and especially Firefox could potentially completely ruin a user experience (such as animation tweening) using this method. Be warned!

Edit 7/11/08: Added Firefox 3.

Edit 9/02/08: Added Google Chrome.

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Comments (2)

  • Unknown user
    July 11th, 2008 Robert said…

    That is very insightful information. I myself never use try catch except where I have no control over possible exception and I expect them, this is very rare.
    I’m not a fan of try/catch :)

    I wonder why you didn’t include Firefox 3?
    I ran it myself with FF3 three times and got:

    Solo: 7ms
    try…catch: 6ms
    try.catch and an error: 19.882 seconds

    Solo: 6ms
    try…catch: 6ms
    try.catch and an error: 19.806 seconds

    Solo: 6ms
    try…catch: 7ms
    try.catch and an error: 19.782 seconds

    Aside from the HORRIBLE performance catching an actual error, Firefox 3 beats all the rest.

  • Matt Hackett
    July 11th, 2008 Matt Hackett said…

    Hi Robert,

    To be honest I wrote this article before FF3 was out and only just recently published it. Thanks for reminding me! I will post an update (it needs to be on the same machine as the initial testing so the speeds remain relative).

    Also World of Solitaire is great! All the YUI guys here love it.

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