错误代码
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<script>
function clear() {
document.getElementById('dd').value = ""
}
</script>
</head>
<body>
<input type="" name="" id="dd" value="1" />
<button id="btn" type="button" onclick="clear()">清空</button>
</body>
</html>
原因:函数名使用了关键词,将clear改成clear1就能成功运行