Add option to all combo on page using Angular

I have some combo on the page.
I may add options to combo using input, input and button.

In link (in Angular directive) I define

element.attr('id','seltas'+index); var z = new dhtmlXCombo("seltas"+index, "name", 10);
z references on last combo on the page so if I used z.addOption() only last combo has new option.

plunker online preview

How can I fix it?

p.s. I devised one knotty decision but it has such long code.


this is awaited behavior. one z = one combo.