title: function with function argument
body: <p>I just wondering to find a keyword or a solution so that I can further find and fix my own problem, so basically, I wanted to call a function but from a function argument, like this.</p>
  
  <pre><code>var arg = function() {/*do something*/};
  
  function do(arg) {
    arg();
  }
  
  do(arg);
  </code></pre>
  
  <p>But I want to put multiple functions on it, but not constant, it sometimes can be 1 function, or sometimes 2 functions or more, is there any solution that I can take? or a keyword to I start searching with? I already searched the internet but I could not find what I want.</p>