Client side validation for select input

I’m not sure the best way to validate a select input where the first option is used as a label similar to example below. And then validate it so it will not except a ‘Blank value’ thus not excepting ‘Select County’ as the selected option.

    <select id="county1" class="form-control" required="" data-msg-required="Please select your county.">
    <option value="">Select County</option>
    <option value="Bedfordshire">Bedfordshire</option>
    <option value="Berkshire">Berkshire</option>
    <option value="Berkshire">Blaenau Gwent</option>
    <option value="Bridgend">Bridgend</option>
    <option value="Bristol">Bristol</option>
    ....
    </select>

How can I achieve this?

Thanks in advance!