StopWatch implemented by Javascript

Sometimes js is required to write some functions for testing. If the test execution time is required, a stopwatch may be required:

StopWatch class:

Function stopWatch () {} stopWatch. prototype. start = function () {this. startD = new Date (); return this ;}; stopWatch. prototype. stop = function () {this. startD = new Date (); return this ;}; stopWatch. prototype. seconds = function () {return Math. abs (new Date ()-this. startD)/1000 );};

Usage (test the Fibonacci series ):

Var sw = new stopWatch (). Start (); (function f (n) {return n = 1 | n = 2? 1: f (n-1) + f (n-2);}) (45); alert (sw. Seconds ());