<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>计时器</title>
<script type="text/javascript">
function changeNum(){
var sss = document.getElementById('ss').innerHTML;
sss--;
console.log(sss);
document.getElementById('ss').innerHTML = sss;
console.log(document.getElementById('input').value);
}
//input元素用value,其他元素用innerHTML
</script>
</head>
<body>
<span id='ss'>5</span>
<input id='input'type='text' value='666'/>
<a href="javascript:changeNum();">change</a>
</body>
</html>
