an</div><br class="clear" /></div></div><div class="description"> Determines if credit card is valid using the Luhn formula. </div><div class="boxWithBorder"><div class="boxedElem"><div class="contentHolder"><span class="title">Parameters:</span><div class="item"><div class="floatbox code colorizedCode">cardNumber<span class="itemSeparator">:</span></div><div>The credit card number.</div></div></div></div><div class="boxedElem"><div class="contentHolder"><span class="title">Returns:</span><div class="item">