HRT(High Resolution Timing) in JavaScript

hrtime.js

var hrtime = (function(){
  if (typeof window !== 'undefined'){
    // browser
    if (typeof window.performance !== 'undefined' && typeof performance.now !== 'undefined'){
      // support hrt
      return function(){
        return performance.now();
      };
    }else{
      // oh no..
      return function(){
        return (new Date()).getTime();
      };
    }
  }else{
    // node.js
    return function(){
      var diff = process.hrtime();
      return (diff[0] * 1e9 + diff[1]) / 1e6; // nano second -> ms
    };
  }
})();