setinterval vs settimeout js

var intervalID = setInterval(alert, 1000); // Will alert every second.
// clearInterval(intervalID); // Will clear the timer.

setTimeout(alert, 1000); // Will alert once, after a second.
setInterval(function(){ 
	console.log("Oooo Yeaaa!");
}, 2000);//run this thang every 2 seconds

var intervalID = setInterval(alert, 1000); // Will alert every second.
// clearInterval(intervalID); // Will clear the timer.

setTimeout(alert, 1000); // Will alert once, after a second.

/*The difference between setTimeout() and setInterval() is that
setTimeout() only executes code once, but setInterval() executes
the code each amount of time you input. For example,*/

/*In this function, it executes a function after 1000 milliseconds, or 1
second.*/
function oneSecond(){
  setTimeout(1000, function(){
    console.log('That was 1 second.')
  })
}

/*In this function, it executes a function every 1 second*/
function stopWatch(){
  var count = 0;
  setInterval(1000, function(){
    console.log(count + " Seconds passed")
  })
}