how do you resolve 'options' is null or not an object in Internet Explorer?

I am currently working on an issue with an e-commerce page that goes to a form to enter your information. The order process works fine but there is an annoying issue with Internet Explorer stating.... A Runtime Error has occured. Do you wish to Debug... Etc Error: 'options' is null or not an object. I looked at the code to debug and this is the particular problem area

function init_state_menu(country_field) {
var country_menu = document.getElementsByName(country_field)[0];
var country_id = country_menu.options[country_menu.selectedIndex].value;
generateStates(country_field, country_id);
}

I ran a test to see if the variable country_menu is defined and it states that is not defined. Any suggestions are appreciated. Thanks