Create drop-down list using JavaScript instead of HTML -

I have the following code that creates and removes text boxes using javascript:

What I'm aiming to do is to create a set of three drop-down lists using this functionality instead of actually creating a text box.

The code for the three drop-downs is shown here:

I got stuck in the form of how to achieve this. I had added the "dropdown" to the div and I was wondering if the inside HTML of this div is to be used to use it to create three lists?

I have another question, how is it that these are generated by Javascript instead of a HTML and rather than a javascript version.

Thanks for any help.

Edit I have buttons to make the next line of 3 drop-down but they do not work by default, Father uses javascript to identify drop-down selection

Code CNA can be found here:

Basic drop downdown Use JS

For example why not use JavaScript such as jQuery libraries. This and many other things will be very easy to make, you can like it:

  $ ('body') Attached ('& lt;! - Any HTML goes here - & gt;')