<html>
<body>
<form id="myForm">
<input type="week" id="myWeek">
</form>
<p>点击按钮返回week 字段所属的表单id。</p>
<button onclick="myFunction()">点我</button>
<p id="demo"></p>
<script>
function myFunction() {
var x = document.getElementById("myWeek").form.id;
document.getElementById("demo").innerHTML = x;
}
</script>
</body>
</html>