function check_form(dd_index)
{
    var error_message = "";
    
    if (document.getElementById('ddlMake_'+dd_index)) 
    	if(document.getElementById('ddlMake_'+dd_index).selectedIndex == 0)
	        error_message += "Please select a Make.\n";
    if (document.getElementById('ddlModel_'+dd_index))
    	if(document.getElementById('ddlModel_'+dd_index).selectedIndex == 0)
	        error_message += "Please select a Model.\n";   
	if (!IsZipcode(document.getElementById('customer_address_zip_input_'+dd_index).value))
        error_message += "Address: Zip Code\n";			
    if (error_message != "") 
    {
        error_message = "Please Fix the following Field(s):\n\n" + error_message;
        alert(error_message);
        return false;
    }
    return true;
}