quick and dirty way to check performance of a javascript function in the console

time.js

function time(func, repeats) {
 var t0 = Date.now(), t1 = null;
 for (var i = 0; i < repeats; ++i) {
    func();
 }
 t1 = Date.now();
 return t1 - t0;
}

// example
console.info(time(function() {
  '1,2,3,4,5'.split(',').join('.');
}, 10000) + 'ms');