I modified /skin1/modules/Product_Options/customer_options.tpl with the code below to display "Select an option..." in the product options select menu. How/where do I modify the javascript to require a selection before adding to the cart?
Code:
<select id="po{$v.classid}" name="{$poname}"{if $disable} disabled="disabled"{/if}{if $nojs ne 'Y'} onchange="javascript: check_options();"{/if}>
<option value="" selected="selected">Select an option...</option>
{foreach from=$v.options item=o}
<option value="{$o.optionid}"{if $o.selected eq 'Y'}{/if}>{$o.option_name}{if $v.is_modifier eq 'Y' && $o.price_modifier ne 0} ({if $o.modifier_type ne '%'}{include file="currency.tpl" value=$o.price_modifier display_sign=1 plain_text_message=1}{else}{$o.price_modifier}%{/if}){/if}</option>
{/foreach}
</select>