Prototype select element with id that contains specific character

Question

I have a select box in admin customer address form like this:

<select id="_item13country_id" name="address[13][country_id]" class="required-entry countries required-entry select required-entry select">
 <option value=""> </option>
 <option value="TH" selected="selected">Thailand</option>
</select>

I need to select country field by using prototype to find which element that contains

country_id

How can I do that ?. Many thanks for your help.

Answer 1

To select element with id "country_id"

$$("[id*=country_id]")

Answer 2

Use $$('$=country_id') to get the elements that have the id ending with country_id and $$('$=country_id')[0] to get the first of these elements.

or use $$('[id*=country_id]') to select the elements that contain the text country_id in the id attribute.
Again, to select the first element use $$('[id*=country_id]')[0]