I am writing a script to tokenize file contents. I've written a tokenizer in JavaScript, but it gets pretty slow with large files (5+ seconds). Since I'm retrieving the files from the server anyways, I am considering rewriting it in PHP to shave off a few seconds. I've read that the speed difference between PHP and JavaScript is negligible, but if the files are 1mb or bigger, a small speed difference could add up. I found this benchmark online, but I'm not sure if the info is up-to-date (with all the JS engine optimizations from the past couple years).
Porting over all my code would take some work, so if I can help it, I won't use PHP. But if its going to be much faster (25-30%), it would be worth it.
Well, like you alluded, JavaScript is executed on the client side, so it would depend on the client. For example, a client on an iPAD wouldn't be able to run those Quake3 HTML5s as smoothly as a client running on a gaming machine. PHP on the other hand runs on the server.
In general, JS is faster considerably than PHP though (on the same hardware);
Here are some [hard figures][1] of tests between the two, to back up my assertion. [JS (query) vs PHP][2] Performance.
[1]: https://benchmarksgame-team.pages.debian.net/benchmarksgame/fastest/php.html [2]: jQuery vs. PHP - Performance Comparison