How to grab all child inputs of a specifc div/form using just javascript?

I saw a similar post here, however I want to do something similar using javascript. Basically there a method to grab all user input in some container such as a div or form

<form>
<div>
   <text>
</div>
<div>
  <textarea>
</div>    
 <div>
   <select>
</div>
</form>

An example would be to grab text, textarea, select, and other forms of user input. I saw something like

var elements = document.myform.getElementsByTagName("input")

But it wouldn't work for selects. I know I could possibly just have a duplicate method which attempts to find ("select") but what if the form must keep the order in which user put in information.

EDIT: Thank you for all the responses. Does all the methods mentioned so far only work if the inputs are direct descendants or is there some other method?