I’ve recently discovered the very interesting Steven Levithan post about the JavaScript’s trim function of the String class.

So, here my version:
function trim13 (str) { var ws = /\s/, _start = 0, end = str.length; while(ws.test(str.charAt(_start++))); while(ws.test(str.charAt(--end))); return str.slice(_start - 1, end + 1); }

More numbers, please!

I tested my function against the benchmarking page of the original post. Note: times are expressed in MS and are the average of ten executions per browser. Update [2008-05-29]: I re-runned all the tests and updated results, because Steven noticed that test suite was wrong (few whitespaces).