gistfile1.js

// =========================
// SetInterval
// =========================

// While not truly accurate, setInterval is still fairly good, time-wise.
// Better for things like a "one second tick" but not great for expensive
// code executed at small intervals as iterations can "stack".

// (ECMAScript 5 strict mode compatible)

// First "arbitrary code" execution happens after ~1000ms, subsequent
// executions follow suit.
setInterval(function(){
  console.log(new Date()); // run some arbitrary code
}, 1000);

// First "arbitrary code" execution is synchronous, subsequent executions
// happen every ~1000ms.
setInterval((function loopy(){
  console.log(new Date()); // run some arbitrary code
  return loopy;
})(), 1000);

// =========================
// setTimeout
// =========================

// While less accurate time-wise than setInterval, setTimeout allows for
// more "breathing room" when executing expensive code at smaller intervals,
// as a next iteration will only happen ~1000ms _after_ the arbtrary code is
// executed and, not _before_ (like setInterval)

// First "arbitrary code" execution is synchronous, subsequent executions
// happen every ~1000ms.
(function loopy(){
  console.log(new Date()); // run some arbitrary code
  setTimeout( loopy, 1000 );
})();

// First "arbitrary code" execution happens after ~1000ms, subsequent
// executions follow suit.
(function loopy(){
  setTimeout(function(){
    console.log(new Date()); // run some arbitrary code
    loopy();
  }, 1000 );
})();