Form Value of drop down category + Translation of 'show option none'

Question

I am building a form where a user can submit an article from the front end..

So far so good... To this form i am doing some submission check using javascript..

When i get to check if a category is choosen

This is the line the retrives categories in the form:

<?php wp_dropdown_categories('show_option_none=---------------->&taxonomy=category&hide_empty=0&name=cats[]&orderby=name&hierarchical=1'); ?>

I dont know how to check it.. what is the value being sent to wordpress? Also.. Can i change this:

show_option_none=---------------->

into somthing i can translate using the regular tranlation method aka __() or _e()??

Thanks guys