<body>
<div class="alert alert-danger">
<p><span class="second">5</span>초 이내 구매시 사음품 증정!</p>
</div>
</body>
<script>
var ssee=5;
setInterval(function(){
ssee-=1;
if(ssee>=0){
document.getElementdByClassName('second')[0].innerHTML=ssee;
}
else{
ssee=5;
}
},1000);
</script>
오류내용
Uncaught TypeError: document.getElementdByClassName is not a function
왜 오류가 뜨는거죠?
