Javascript Asynchronous Loop with clearing

example.js

// do something
var doSomething = function() {
  var myLink = $('a#ajax-link');
  if (myLink.length > 0){
    myLink.hide();
    stopDoSomethingLoop();
  }
};

// do something every 300 milliseconds
var doSomethingLoop = window.setInterval(function() {
  doSomething();
}, 300);

// halts check once button replaced
var stopDoSomethingLoop = function() {
  window.clearInterval(doSomethingLoop);
};