How do you get a timestamp in JavaScript?

Question

How can I get a timestamp in JavaScript?

Something similar to Unix timestamp, that is, a single number that represents the current time and date. Either as a number

Answer 1

For a timestamp with microsecond resolution, there's performance.now:

function time() { 
  return performance.now() + performance.timing.navigationStart;
}

This could for example yield 1436140826653.139, while Date.now only gives 1436140826653.